Too many mobs and unbalanced game

I´m an experienced PC RoR2 gamer. I love this game so much, so I bought it for my switch to play it when I´m not home. But I can´t compare the PC version to the Switch version.
For me it is impossible to get over Stage 1 solo. I cleared the whole stage, then activate the teleporter and so fking many mobs spawn that I can´t defend with the first character.
I am on the discord server and always searching for players, but there aren´t many switchers.
Yesterday I played the game with one other player who was very experienced in this game. I dyed at stage one very often, but he managed to finished it anyways. But we never got over stage 5. If I compare it with my PC experience it´s nothing! I can´t unlock the other Characters because I die always and never go over stage 5.
I bought this game to play it Singleplayer…
The best solution would be to get the first character more damage and let spawning less monsters on the first stages or make the number of monsters depending to the number of players
(especially if the teleporter gets activated.)
It´s not a 10 Bucks game, so I expect a playable game, for singleplayers too.
Best Regarts