Tbh (sorry previous poster) I’d probably avoid La Rambla unless you’re staying in the upper part, above Plaça Cataluña. There’s a lot of improvement work going on at the moment between Placa Cataluña and the bottom where it meets the sea and it’s noisy, plus you have the usual pickpockets, tat shops and pigeons.
If I had to book a trip and money wasn’t an issue I’d go for the Ohla. Lovely restaurants at both locations. You won’t get a sea view at either though.
Eixample is generally safe and well connected. My favourite part is the bit around Enric Granados and Majorca - you’ll be swimming in lovely restaurants and bars there.
Poble Sec and St Antoni are ‘up and coming’ aka often a bit grubby round the edges but there’s lots going on and enough hipster type places if you’re into that kind of thing.
If you want to see the sea from your bed the Barcelona Art Hotel or the W are your best bets, though you’ll have to walk a bit further to do stuff like buy a coffee.
The weather is lovely (and far too dry) at the moment so you’ll be able to stroll everywhere comfortably. Bear in mind there’s an ongoing drought (4th summer) so we’re officially in a state of emergency, so please take care with water consumption. Also, the grass will probs look a bit brown 😂
Happy to give more info, I could write a book on this as a local.