Hi, I've had this issue for a few weeks now and I have found it only happens when using Virgin Media broadband.
I work from home and have a work-related web site that worked fine up until some time between me going on leave on the 9th Jan and returning on 6th Feb and now when I try and access it, it works intermittently. Sometimes it loads fine, other times it doesn't display at all or only partially loads, and even after it successfully loads, it will stop responding after just a few clicks.
I have done some diags and found that the issue only affects me (colleagues are fine), and only when connected using VM. If I hot-spot my phone (Vodafone) and connect 2 different laptops via that, the site loads rapidly and works consistently as you'd expect it to. I can also access the site if I use PIA VPN (which I cannot do on my work laptop, obviously). I have raised support tickets with the site maintainer and they can find no issue, but considering its a problem specific to me, when connected via VM I wouldn't expect them to.
If someone from VM could message me I will provide the site address but obviously I'd rather not post it on a public forum.