I saw a new television which probably supports the functions of the ps5, now I wanted to ask you whether this is really the case?

Here is the TV which I will probably buy today, according to the description it has hdmi 2.1 and 100hz

https://m.alza.at/55-lg-55nano863na-d5861786.htm?kampan=adw_alza_pla_all_alza-ultrahrotove-segmenty-vieden_Produkty_m_1000772_WK612d03

I generally can't find a DVB-C or DVB-S tuner in the description. DVB-T2 is terrestrial television via the house antenna and has nothing to do with cable television.

100 Hz would be too low for me. I also can't see anything from the support of the PS5, and I wonder what should be supported.

I mean something like hdmi 2.1

Well, multiple HDMI connections should be standard on new televisions.

But as far as I've seen, HDMI 2.1 isn't a standard that often

Presumably because it is only now with the new devices. I can't say whether it's really much better. It's like USB 3.0. It took a while for that to happen, but I can't see any major difference.