Best Of

• The first step is to design the lowpoly precisely according to the reference art/high poly, placing edges to support these details (like, for instance, having an edge that runs along the connection between boot and sole).
• These edges can also be used for UV splits, that way material separations will be razor sharp and will never depend on texture resolution.
• You can of course also control the baking rays with a custom cage to avoid wavy cylinders, but that's a bit of an obvious one.
• And lastly, you can also rely on manually editing the resulting textures. And this will be especially easy and relevant if the UVs have been split along material separations.

Overall you need to let go of the idea of baking begin a blind "retopo then UVs then hit bake" chain of events because it really isn't. The quality of the result almost fully depends on the way the lowpoly geo is built ... just like with old school "pixel based" texturing on ps1/ps2 era models really. You will not be "fixing" these distortions, you'll need to model your low with them in mind in the first place. But of course if this is your first time with all this this is a bit of a chicken and egg thing :D

Here's an extreme example of the principles above :

Also note that this model didn't even use a highpoly to bake from - the whole look comes from applying the principles above + adding a nmap bevel all around the panels. But of course it could receive baked highpoly details too.

One last remark : once your lowpoly and UVs are taking shape you can also take a few minutes/an hour painting in landmarks with a simple brush, just to get a feel of how the texture distortion will behave.

I can only recommend the study of models from Nintendo games, they are extremely tight in all these areas. That's the beauty of them always developing on low-end hardware, as it forces them to make pristine assets that look good even with lowres textures (while avoiding the pitfall of spending days on highpoly models).