52 is not a factor.....multiple guys in their 50s have been hired at AA over the past several years....think the record was a few flow-thrus that were 63....couple guys were 64 but retired before finishing training.
Lack of 121 experience is working against you.....Put your stuff in at Envoy, upgrade quickly, you can apply and get hired at a major or flow thru well before you’re 60. Or you might decide being an E175 Captain with a good schedule and some seniority is good enough.
One thing is true.....if you don’t apply, you’ll never get hired