To the best of my knowledge, the only plastic altos you can get at A=415 are the Bernolin you already know about, and one from Aafab/Coolsma, which you can look at here. NB the Coolsma costs the best part of €2000 so makes the Bernolin look very reasonably priced! I know someone who has the Bernolin soprano which they say is an excellent instrument.
For what it’s worth, I don’t like the Zen-On alto, though that’s purely subjective and I know people who do like it. I can highly recommend the Aulos Hakka.
“Tuned for Baroque” probably means in most cases that they have Baroque (aka English) fingering rather than German fingering. Instruments in A=415 (or other “baroque” pitches) tend to be either top-end models or hand made, thus expensive in either case.