I've been on keto for 4.5 months now and I've lost three stone. I have a long way to go weight loss wise and that is my main goal but i have experienced other benefits too. Once I've reached a weight I'm happy with I'll stick with low carb to maintain.
I had keto flu but it wasn't too big of a deal as I kept on top of my electrolytes and drank plenty of water.
I don't eat out anyway because I have young kids and no money = no social life. However, I could easily pick a few meals that I could order from the menu. There is no harm in asking them to adapt it to suit you.
Keto is not a quick fix. Yes you can lose quite a bit in the first couple of weeks so I understand you think this is a good option to prep for holiday, but it will be water weight that you lose and as soon as you start eating 'normally' again on holiday you'll put it back on.
The bloating you describe is most certainly the carbs that you consume and this will decrease massively if you follow even just the basic principles.
Another thing to be aware of is that there are "versions" of keto, i.e. dirty keto - where you consume fewer carbs but by eating rubbish such as 50% pork sausages containing potato starch etc versus clean keto by eating 97% pork sausages with no inflammatory ingredients.
This way of eating is very much about removing the processed, added crap as it is about limiting your carbs.
I'm part of a clean keto group on Facebook and we stick to 20g carbs or lower per day. You can easily eat 3 meals a day but after the first 4-6 weeks most eat 2 meals or OMAD (one meal a day). I'd be happy to send you a link if you want to join the group and research, read the files, look at success stories etc. The group are very supportive and knowledgeable.
Calories in/out is old news - you don't need to be at a deficit to lose weight in a healthy way.
The awful relationship I had with food is no longer an issue for me. I haven't gone hungry, I don't feel I miss out and I have so much more energy.