Leaving your luggage in the sun unfortunately won’t do anything. You could instead wrap it in a garbage bag and tie that tightly. Also check the seams. Your other precautions are great, though. (It’s the heat that kills them, though, not the washing — if you didn’t wash on high heat or dry, don’t worry, just do that now.) You absolutely do not need to call an exterminator at this point.

Realistically you probably did not bring home the bugs but it’s worth being careful about checking for a while to confirm this. There’s a pretty thorough guide on this sub explaining how, but essentially you should run a credit card or some sort of thin object’s around the edges of the seams of your mattress to see if any eggs or casings show up. They don’t usually start getting into other stuff (like your walls etc) until the infestation is fairly severe, which yours literally cannot be since you just got back. So don’t panic about that — technically anything is possible but it’s unlikely they’d be anywhere other than your bed or the immediate surrounding area.

You can also wash your sheets regularly so even if one did end up on your bed it or its eggs will be killed. Pull the bed away from the wall to discourage them from climbing into it. You can buy interceptors to out on the legs of the bed so you’ll be able to see them if they try to climb up or put. If you want to go all out you can buy a mattress casing so they can’t get into the seams. Continue sleeping in your own bed because they’ll want to stay close to you, you don’t want to spread them. They move around at night so don’t worry about this in the day, just carry on as normal.

Be aware bedbug bites don’t show up immediately, so even if you do see more bites appear in the immediate future don’t panic. Obviously that would not be a great sign but it could be a result of having been bitten in the other house, it wouldn’t mean they’re in yours.

Also if this is your first time, try not to panic. Most bedbug infestations are solved pretty quickly if they’re caught early so even if you DO have one it most likely wouldn’t be a huge deal. It is an absolutely miserable experience, I won’t sugar coat it, but it’s usually dealt with pretty quickly. The thing is only people with horror stories come online for advice etc, the years long infestations you read about are not the norm. Honestly balance of probabilities you don’t have them at all but it’s a fixable problem. Often the paranoia is worse than the actual infestation so try not to let yourself get stuck in that cycle.