FWIW, I have an M1 iMac with 16GB RAM and 1TB SSD. I do almost all stills with the latest LR and PS plus the usual Apple software and Microsoft 365. I keep 3 months of everyday photos on the internal SSD and projects and the archive on external portable SSDs. My cameras are Fuji X series, so 26MP, but if I am printing big, I use super resolution to upscale to 104MB, and am very happy with the speed with which these are handled with both LR and PS open at the same time. I swap from LR to PS and back via the Edit in tab and return to LR, all working fast. Incremental Time Machine, which I use once a week, takes about 10 minutes to a SSD.
Perhaps this config or better may be OK for you, and maybe Apple refurb may have a suitable machine if you do not want to buy new. SOC on Macs has made a big difference. I do not know about Macbooks as I want a bigger screen and do not want a second screen for a laptop.
Happy hunting.
Jonathan