My personal experience with Bettas in a community tank is they get killed very fast, and quite violently. First community tank betta aggravated the wrong discus and I watched helplessly as he got shredded, adult discus can do damage and do it fast. The second on got chased out of the tank (kept finding him hiding on the spray bar) by bleeding heart tetras, a school of them.
. It's ok not to want a fish, just admit it. Don't blame it on the fact that a known jumping fish jumps and you 'have no lid'. Not to come down on you but sheesh, Oscars are my favorite fish & so few people give a flip about them.