AITA for not getting my friend a wedding gift?

I’ve been friends with a girl Vivian for 8 years. She got engaged in September and her fiancé contacted me to do their engagement/pre-wedding photos unpaid. I’m a photographer (not full time). It took me about 10 hours to sort through and edit (with them constantly asking me despite me having a full time job in the meantime), but since they’re friends I didn’t complain or ask for anything in return, and they were ultimately incredibly happy with the photos. I did bring up in passing how I am also busy with other photography gigs and I need to prioritise a customer that paid extra for a fast turnaround, and Vivian and her fiancé told me ‘in that case take your time’. However they did proceed to text me three times asking for specific photos before they were done. They never offered to compensate me, although I never specifically hinted, and my other friends who asked for photos had always given me a small token of appreciation (even just a home-cooked meal) if they couldn’t afford to pay. In their case, I know they could afford it, as the fiancé did reveal to me he considered getting a professional but decided he liked my style better.

They are getting married in a month (things move fast) and have decided to have the whole wedding in China where their extended parents live instead of the UK where we all grew up. This means that I will have to take at least a week off work to fly there (the wedding dates run from Tuesday morning to Wednesday evening) and with the jet lag, it’s not worth going for less than a week. For the wedding dates, they have booked out a whole hotel (their parents know someone so rented the rooms out to them for free), so my husband and I won’t be paying for those nights, but we still have to pay for nights before and after, return flights (£1000 per person) and travel within China.

I definitely want to show up and be there for Vivian so not attending isn’t an option. It’s also my first time in China so that’s something. I have to add that when I got married last year, Vivian and her fiancé did not give us a card or a gift and the wedding was a 30 minute drive from their house. We also paid for our wedding, whereas their parents are paying for theirs, which means that they wouldn’t need any money to help pay for the costs. I don’t know if I’m being petty, but since they didn’t give us anything at all, we’ll have to pay a ton of money just to get to their wedding and how I did a few hundred quid of unpaid labour for their engagement, I don’t think I need to give a gift (or cash). However, if we don’t gift anything we will might across badly. AITA for not buying a gift for their wedding?

TLDR: I did an unpaid photoshoot for my friend’s engagement and pre-wedding, and said friend didn’t give me a card or gift for my wedding. Her wedding will cost me over a thousand pounds to just get to. AITA to not buy a wedding gift for her?