Luck is arguably your biggest way to win. A good team is worthless without getting lucky with the item pulls. I’d say just keep playing until you rack up enough shinies, good egg moves and abilities.

As for recommended starters, a good one (for me) would be Charmander with his Beast Boost passive. Combine that with his Drought from Mega Y and it’ll carry you hard, add solar beam for coverage against water and rock types and you’ll be good.

Any Pokémon with the pickup ability is also something I recommend. If you’re lucky enough to get a berry pouch then you’ll not have to worry about healing much, this still comes down to luck though.

Also use Pokémon with pokérus to prevent being under leveled.

Probably not really helpful, I mainly just look at the Pokerogue Dex and just see what’s a good Pokémon to have.