Just to add to the debate, my 7530 was bought in April 2021 and is still going strong. It is now acting as a router on PlusNet full fibre 300 using the LAN1 port instead of the ADSL WAN port. It also acts as a DECT base station for two Fritzfon C6s via A&A VOIP.
I'd say it has stood the test of time in terms of keeping up with the technology and given excellent value for money.
Looking just now, the 7530 is still available new on Amazon (UK) for £168, with the AX (WIFI 6) model at £250.
I think the fact that Zen chose it as their standard router says something about the quality. They obviously thought it was (is) reliable.
On the few occasions I have experienced issues, it was my own fault, and AVM support were quick to sort it out for me.
Cheers,
Axolotl