Honestly it's a combination of the battlepass system and the stage design causing constant, very fast-paced combat. The stages are too small, so players are funnelled into the middle of the stage. This also causes spawncamping if the matchmaking is even slightly unbalanced (which it is most of the time), as one wipe will allow a team to push all the way into spawn.

Previous Splatoon games were very good about this - most stages were abstract shapes, with a lot of terrain, meaning combat was rare, and the game encouraged painting over fighting as painting would net the most points on a per-match basis. Splatoon 3's new maps are all thin, straight lines, which forces players into that central killzone.

The battlepass, along with some very poor decision making around the results screen, which shows the winning team celebrating, means that losses feel bad. The matchmaking similarly punishes winstreaks by forcing losestreaks, usually matching you against people above your skill level, but on a team with players below your skill level. Whilst this is very addictive, it makes losing feel genuinely awful, and a losing streak causes tilting due to the FOMO of the battlepass.

Hope this writeup makes sense. I view Splatoon 3 as a genuinely bad game because of these factors, and greatly prefer Splatoon 2.