From what you describe, 8GB on a new Mac should be more than enough. I do far more demanding and intensive things than you do on a low-end 13” 2015 MacBook Air with only 8GB and it works great.
If you look around MacRumors, you'll find lots of threads debating what the minimum amount of memory is. Many endorse the 16GB as essential or for “future proofing”, while many others persuasively argue, from experience, that 8GB is sufficient for what they do and what you do.
For browsing, email, online banking, and storing photos, 8GB should stand you in good stead.
You absolutely do NOT need an M3 Mac for what you do.
You could do quite well, enjoyably so, with an M1 MBA. Depending upon your photography work, and whether you want all your photos and videos available on your computer, you could opt for 512GB.
If you're looking at a desktop Mac, SSD capacity might not even be that crucial as you could even rely on an attached SSD for photo storage and another for backups.
Apple sells refurbished Macs that are like new and carry a full 1-year, with optional Apple Care, so you can save money that way, too.