There was a similar thread recently RPi 1B + PiCamera V1.3 - Auto Calibration (SOLVED!) . If you have the ability to work with Gitlab, there is a solution for the Pi Camera 1.3 PiCamera v1.3 support (!178) · Merge requests · OpenFlexure / openflexure-microscope-server · GitLab. @pbrugugnoli contributed this.
A Pi 3B will be fine, we were pretty much unable to use anything else until the middle of last year with the shortage of Pi4. If you use it from another computer with the lite version of the operating system (no Pi desktop) it will not even be slow.