My recommendation would be to check the likes of ebuyer and search for Gaming Pcs.
Read the reviews.
Maybe watch the Graphic Card Spec and the power supply.
Graphics cards can be replaced, so it may not be a big deal to purchase with a low end graphics card.
Even the best gaming pcs can not run the new flight Sim on ultra settings. But you can have a great experience on a £250 Graphics Card.
Its not like the old days, where you needed to spec everything twice, reviews from owners are a great guide.
However you may also consider a dedicated gaming machine like ps5 etc..
Hope that gives you some guidence.