Its the SH your using, its not fit for purpose for Gaming.
Go modem mode, and get your own router. Its the best way.
I have been in Modem mode, with a SH, SH2 / AC, SH3 and now an SH4. I never have any lag issues, I game on a PC / PS4 and PS5, all via wired.
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Red (VM SH2 AC Beta tester)
Running on 1Gbps VM service with SH4 in Modem Mode, with a ASUS GT-AX6000 router. With this setup I get Fantastic WIRED and WIRELESS Signals in my home. I dont work for VM. But I work in IT, and I know my tech.
My advice is at your own risk. If you are happy with my answers please press Kudo ?