The UK is not under any real level of restriction, and the (own-currency) debt taken on is not of a form that would harm growth. Compared to its peers the UK is doing abysmally; the distinguishing factor is Brexit.
So far as I have heard, the UK went way harder into lockdowns and other measures than the US. And from what I saw, what happened to the US was insane. Everything was closed down for months (or longer depending on the industry.) Supply chains were incredibly disrupted. The government went deeply into debt and inflation is skyrocketting. There are still shortages of many things for the forseeable future. Unprecedented numbers of people have lost their jobs.
I literally can not imagine thinking this is comparable to any other economic event, since the world wars or great depression anyway.
The UK did lockdown somewhat harder than the US (but not some US states), but that mostly only affected hospitality and entertainment, and home-based activities made up for that to an extent. The debt is inconsequential (for now), and inflation is still nothing compared to the '70s.
US GDP is around 2.5% below pre-covid trend; the UK is far behind that. UK exporters (and importers) have taken a huge hit from the new trade barriers.