,em>Can one assume a chumra for oneself if he feels it will help enhance his Torah observance?
Yes. If it will lead to yuhara, then by definition, it’s not an enhancement of his Torah observance.
Eruvim is a tractate in the Oral Law.
Absolutely. I meant most contemporary eruvin.
And the overwhelming majority of poskim permit a public eruv under at least some circumstances.
If you mean contemporary eruvin, I agree, but that doesn’t mean it’s not a kula. There is legitimate place for utilizing a kula under some circumstances.