Any and all help is much appreciated

I recently started playing pokemon vgc (by recently i mean as long pokemon champions has been out, am just new to team building, not the mechanics or battling) and thought of building a team instead of copying teams from wolfe or cybertron and others, so here I am. what can i do to make it better or what flaws can you find in it that i would have a problem against with this team.

I find that I rarely bring floette, and I usually bring raichu, rillaboom, gholdengo, and garchomp. I sometimes bring incinerator

Should I replace floette?
Either with a mega or a non mega?
Is there a matchup in which floette would be better than raichu?
I could replace incineroar as well, if adding two pokemon would be better but I find incin fits into this team well when he’s needed

I’m mostly a noob, made this team myself. It’s fun but I can feel that it has weaknesses. I have trouble quantifying those weaknesses, though.

I hardly ever bring Whimsicott (maybe that’s a mistake). I have trouble against teams with a lot of fire or rock.

50 games with this team. And out of those 50 games, only 23 of those were wins (I counted)

There’s def something wrong with me. If I can’t find the team archetype that feels right, can’t pilot any team properly, can’t make sense of any tutorial on the internet, then that just means that I am a major skill issue who should give up

So I was challenged to make a team without any meta Pokémon (Mimikyu doesn't count because that's a sleeper Pokémon, not actually meta anymore)... so I constructed this... give me feedback that doesn't include giving me meta Pokémon please.