WIBTA if I were to gift my sister a budget planner for her birthday?

Hi, this is my first time posting, and I wanted to know if what I am considering in doing would be a good or ***hole idea. Plus, I am worried of the worst case scenarios.

Context [Apologies if it's long]: I (34F) have a little sister (30F) who I'll address as LS. I'd say one of the issues that I have seen with LS is money.

To make a long-story-short, it put a strain between her and our older sister's relationship (37F who I'll address as OS). A couple years ago, OS has let her stay at her place on the conditions of contributing (paying bill portions, making some meals, babysitting, etc.) and it was fine till it was not; especially since OS is a single mother who has to balance her job, her two kids (my niece and nephew), and she too has her own concerns with money.

One of the big heated arguments is LS failing to pay fees for a storage unit and intentionally hiding the mail notices. When OS found out she verbally lashed at LS, because by the time OS learned about it, the storage unit was sold and everything that was stored in there was gone. A good amount of those items were things our dad got for our niece and nephew before his passing in late 2020. I was miffed when OS told me sometime afterwards, cause another item now gone was a bike I bought for my nephew as his birthday gift that he only got to use a few months before it was stored for the winter months.

Last year, OS put her foot down and told LS that she had to get a job AND at the very least pay part of the utilities or else she would be kicked out. LS eventually found a job at food service (OS had to pull teeth with her with updating her resume and sending it out). As of last Christmas, LS still has her job, is currently in a relationship with an old neighborhood kid and has her own car.

As I said, the relationship between OS and LS has been strained. OS has had conversations with me once in a while regarding LS of what happened these couple of years. To sum it up and paraphrase what OS said to me: "I'm losing my trust and reliance with LS. I don't know what happened to the sister that has been supportive, always there to help, and be there for my kids; her niece and nephew. To the sister who has helped and defended me, and called out on my ex (niece's and nephew's bio dad). I swear, her behavior is becoming like my ex." [This was a mental "yikes" for me, because to say the very least, her ex is still a deadbeat, and that's the only nice thing I can say about him.]

Now between me and LS, our relationship isn't bad, but we haven't spent time together outside of special occasions. I do have a couple of issues with her (Also money related). One of which is that she owes me some hundreds of dollars from lending her funds to help her move into a new place after we were moving out of our old place five years ago. She still owes me to this day.

This year, since she got her car, she has been asking me for money for gas and promises to pay me back when she gets paid that same week. Luckily, she'll asked between $20 to $40 at most and it will always be for gas to get to her workplace. At times, I've sent her the money needed. Other times I tell her I can't, due to my budget and planning and she respected that. And when I can afford to lend her the money, she at times pay me back as promised, a few occasions she'll pay me back the following week or a few weeks later. Note her asking ranges between every other week to almost a months time.

Her recent asking was a few weeks ago mid-November on a Thursday. She asked for money for gas. I was tight on my budget for the month; I had enough to cover rent, groceries and some funds I set aside for a weekend volunteering (covering transit and food costs). I already paid my bills. I told her: 'I can't, sorry.' She said: 'Okay.' In addition, I asked her if she'd got my voice-mail in regards to what she wants for her birthday in December. She said yes, but wasn't sure, so I asked her to let me know by next week so I can get it on time if I have to order it online.

By Tuesday, I only had my money to pay my rent (Bought groceries on Monday). I was at work when I got a call from LS. She asked me if I could lend her money again for gas and said she already knew she asked last week about it but was hoping. I told her I needed that money for my rent and I need to have it ready at the start of December. She insisted that she promised to pay me back on Friday and understood the inconvenience. So I transferred what she asked. In that call, I did remind her that I need to know what she wants for her birthday. She asked about the budget for her gift, and I said $80 max.

Thursday comes and she texted me a list of a few items for her birthday and briefs on she doesn't know what else she wants. That's fine. But I did remind her that she needs to pay me back tomorrow as promised, and she said okay.

Fortunately, she did pay me back on Friday as promised.

Now it's December, and I'm figuring out my funds for this month in addition to my current bills, expenses and of course the holiday shopping. I only need to get one Christmas gift, and of course LS's birthday gift. I've checked the list and relatively easy to get. One of which was a planner agenda. Then out of curiosity I searched budget planners, and at the back of my mind the thought to get it was tempting.

It be good to gift her the budget planner and the other items she asked. Although, I'm also second-guessing myself that LS would react badly to it. It's a mixed complication. As much as I love my sister and helped her on occasions for things outside of money, it's frustrating that she should be wise on how she handles certain aspects of life and not relying on someone to help her. Cause what happens when one person you rely on can no longer help, or needs to rely on her if they ever in a moment of needing help... She has helped at times when I did asked for some favors, and other times she can't and I understand...

So fellow potatoes and Potato Queen Charlotte, WIBTA if I were to gift my little sister a budget planner as part of her birthday gifts?