Retirement Questions about IRA and thinking strategically about taxes

I (43, F) am a single mom (donor, no child support). I’m in an expensive city and am still saving for a house, but I also want to make sure I’m saving enough for retirement (hoping to retire by 65).

I had a few false starts in my career and was paying off grad school and other family obligations, so I didn’t really begin saving until my early 30s. I have no debts now and want to be smart about setting up my future.

Here’s what I have for retirement: $637,000
401k: $310,000
Brokerage Account mutual funds earmarked for retirement: $125,000
Company Retirement Savings Plan*: $120,000
IRA*: $82,000

* I did not have a 401k for most of my 20s/early 30s which is when I contributed to the IRA. Then in my first year with a 401k, I still contributed but was cautioned by a friend to not commingle money in the IRA from years when I did not have a 401k to when I did, so I stopped contributing and instead earmarked a mutual fund in a brokerage account for retirement.

Contributions
401k: I max out my contributions each year. My employer will match 4%
Brokerage Account Mutual Funds: $1000/month

Company Retirement Savings Plan: my company contributes 4% of my compensation. This % will increase with my age/years of service. I’ve been with the company for 5+ years but it’s an industry susceptible to routine layoffs so I don’t want to count on future contributions.

Questions

I’m fairly new to even thinking about retirement and am not sure even where to start so please excuse if these questions are basic.

1. IRA: I currently contribute to the 401k and the brokerage account mutual funds earmarked for retirement. Should I redirect some of the brokerage account savings to an IRA? Because I already have an IRA where I commingled funds from years I did not have a 401k to years when I do, should I open a different IRA if I begin contributing to an IRA?

2. Taxes: Is there anything I can be doing now that would lower my taxes in retirement?

3. Amount: I really don’t have a good frame of reference. I’ve been trying to make up for lost time. Am I behind or on track for saving for retirement?