"Just jailbreak your phone and install <blank>!" they said.
I did that for a while, depending on some random guy in a forum to maintain a working image for my device. He bought a new phone, and that was the end of the updates.
With Play Integrity / SafetyNet this is also an uphill battle without doing even more work to spoof your Integrity status, if you want mobile banking and finance apps to work.
I bought a brand new flagship phone for $1100, couldn't jailbreak it, then the manufacturer got bored, forced an update that bricked it, then got bored and never published an update again.