Жить - живу, шить - шью

stems бий+ вий+ лий+ пий+ ший+ =>present tense бьй+ вьй+ льй+ пьй+ шьй+ normal first conjugation verbs,
add ending and proper spelling => бью бьёшь бьёт бьём бьёте бьют
infinitive add normal ending with spelling rules. => бить
imperative: бей,
past: бил etc.

stems мый+ рый+ вый+ ный+ крый+ => present tense мо'й+ ро'й+ во'й+ но'й+ кро'й+ add normal first conjugation endings with spelling rules
мою моешь моет моем моете моют
infinitive add normal ending to stem мыть
past, normal from stem мыл etc.
imperative: мой
Normal spelling rules for reflexive.
etc.

Most verbs are easier than these.

Stem for жить is жив+ all normal spelling rules for adding consonant and vowel endings work fine. Consonant ending root/stem stress pattern (that is not й or н), with the stress shift sign for feminine past, that I could not add from this computer.

One stem is usually enough to do complete conjugation for all forms.

Of course, non-Russians have to learn all the rules about consonant mutation, and a few other things. If you want two stems, you can have two stems. The fraction of verbs with complications is small.