Haven't seen this bug before: when Raid Loots are active I receive only about half of profits if Midas Gold's working in a background browser tab. I now use Felice with her energy mode.
Highguard, difference between Valeria and Adeline is diff between Mana and Energy mode. Check that you activate Divine Knowledge for Valeria. And yes it could be that passively next hero isn't much better then previous, though I never measured.
It's hard to analyze and plan investments since building Gold Profit stat is almost useless because we don't know exactly building Time. And if did know this Time stat we would need to divide Profit by Time to compare buildings. You should change useless Gold Profit to useful gold per second stat
AlgaeNymph, there is now such thing as autocasting in this game. At least I haven't seen it while getting up to cave 35.
But mana is used for resurrection of heroes. So if you've turned on Auto Battle and with 2x you may have problems with mana accumulation.
Solution: turn of 2x accel. and, if not enough, auto battle
A small design flaw: if you press Gems tab you'll receive 5 of them in 10 seconds. But after using Gemrise spell once and pressing Gems tab again you'll get only 2 of them in 10 seconds. Yes, I receive more with Gemrise in time but this particular moment feels like downgrade
 "Midas' Gold Plus")
 "Realm Grinder")
 "Tap Adventure: Time Travel")
 "Factory idle")
 "The Boulevard Theater")
 "Cave Heroes")
 "Evo Explores")
 "The Perfect Tower")
Fixed. Thanks for report.