Chimera is indeed meant to be a suicide mutation line.

The right way to do it is to be very careful.

Before mutating, prepare an expanded digestive system.

You also want to be an unarmed melee expert, or use a very light weapon(more mutated part procs).

Prepare a meat freezers with at least 2 full moose of meat. About 2000 units of meat is the recommended amount. Or 500 units of fat. A mix works best.

Only mutate when your phenotype is not even spent.

Prepare mutagen chelators so you don't overshot and end up taking legitimately all the bad mutations.

That way you only get the clean mutations at first.

Then, once you start wanting the mutations that alter your body rush all the way to threshold and above and if you get all the ones you like, use the chelators to stop the process.

With luck you should get a functioning Chimera.

If you want an actually strong mutant, I would suggest mouse primary, with bird and fish booster mutagen.

You end up with a character so fast you may as well be teleporting, loves the numerous junk food, has advantage on range combat(reduced detection range), does'nt need water, does'nt drown in water, can't be hit in melee(mostly) but has truely rubbish carry weight, but you teleport anyways so does carry weight really matter. (It does, many button press hurt thumb, cart-holomew best friend though)