The Bitcoin system has 7 mining-nodes:

Foundry USA - 119.8 EH/s

AntPool - 104.6 EH/s

F2Pool - 52.6 EH/s

ViaBTC - 42.48 EH/s

Binance Pool - 38.39 EH/s

http://BTC.com - 8.09 EH/s

Poolin - 2.6 EH/s

Why there are not mining pools using exclusively only Stratum V2?