I take care of my car - regular oil changes, etc - How many more miles can I expect from this engine. It runs fine -no problems.
There is no way of knowing the answer, but keep doing what you’re doing obviously. It seems to work.
My brother-in-law put 450k miles on a Chevy 350 truck with no engine problems; and this truck was used commercially and saw some fairly hard driving during that time.
If it runs well, why worry? If you start to replace drive train parts or notice an increase in oil usage, you can start fretting again. Drive it, enjoy it.