This.
But with additional advice on the basis you are on your own. And based on growing up in a big BBQ culture (non UK) that BBQ pretty constantly during the summer. Once you get your head around the fact it is just a meal outdoors, it is a game changer and much easier than putting pressure on yourself to do "something different".
First don't over complicate it. Cook a few things very well. We rarely do sausages and a burgers on the grill. We tend to do big joints, steaks, fish and kebabs (not all at once) and keep it to no more than two different meats/fish plus a veggie option at any one time. Anything you can marinate in advance and nothing that takes prep once the guests have arrived so all you have to do is cook it. Also don't feel bad about mixing up precooked/oven baked food with BBQ food. A good BBQ cook book is a god send for beginners.
Vegetarian BBQ - Haloumi is your friend here. But hassleback it and marinade it. Otherwise it falls to pieces on the BBQ. Corn on the cob is also easy. Jacket potatoes, started in the oven, in foil, finished off on the BBQ.
Second. Focus on sides. Most UK based BBQs tend to have the sides as an add on and they end up a bit limp and underwhelming. 2 to 3 really cracking sides, plus fresh bread elevate a BBQ beyond normal. Find a few really effective tried and tested salads, don't be afraid to mix a match curry, rice, carribean, Mediterranean dishes. Also don't feel bad about serving something like chilli alongside main BBQ meats.
Third, Keep desserts simple or get your guests to bring them.
Fourth, consider decent disposable/environmentally friendly tableware. Or make sure your guests help tidy up.
Finally, Have a couple of camping tables you can put up to help with managing worktop space around the BBQ. And grill pans can help manage things like fish and kebabs on the BBQ too.
And if you hate BBQ ing, just do a lovely outside meal/buffet. People just love eating outside with friends. The food - as long as it is good and plentfiul - really doesn't matter.