Charcoal grey, plain, no stripes, is definitely the most versatile colour for a suit.
Single breasted, 1 or 2 (3 if it fits well and suits your body shape)button jacket, flat fronted or single pleat trousers, standard notched lapels, no turn ups on the trousers, nothing too fancy or “fashionable”.
It’ll do all occasions.
Whatever you do do not buy one of those skinny trousered, short jacket suits that are doing the rounds. They might look ok poncing around shoreditch, but turn up to a job interview or a funeral in one and you’ll just look like a ****.
So many suggestions for where to buy so I won’t echo them. Just try a few and buy the one that fits best.
Job done.
(I said earlier that here was the last place I would come for fashion advice and here I am doleing it out, I am aware of the irony)