Looking to meet people while travelling across Europe

Hey everyone!
I'm travelling around Europe from 25 August to 8 September and would love to meet some other travellers along the way. I'm travelling solo in Valencia, then a friend is joining me in Madrid and we'll be travelling together for the rest of the trip.
My itinerary:
🇪🇸** Valencia — 25–29 August
This is the solo part of my trip. I'm going to La Tomatina on the 26th 🍅 and would love to meet other people doing it. I'm also planning to explore the old town, hit the beach, try some good food, and hopefully join a boat/catamaran party.
🇪🇸 Madrid — 29–31 August
Meeting my friend here. Planning to explore the city, eat, drink and experience some of the nightlife.
🇭🇷 Split — 31 August–4 September
We're hoping to do some island/boat trips, beaches, explore the old town and enjoy the nightlife. Definitely keen to meet other travellers here too.
🇳🇱 Amsterdam — 4–8 Septembe**r
Exploring Amsterdam, doing some sightseeing and potentially a day trip before flying home on the 8th.
I'm mainly looking to meet people rather than necessarily find someone to travel the entire route with. Happy to meet for an afternoon, dinner, drinks, a night out, a boat trip, sightseeing or whatever else lines up.
If you're going to be in any of these places around the same dates, let me know! It would be especially cool to get a group together for Tomatina or a boat/island day in Valencia or Split.
Feel free to comment or send me a message — always happy to hear about other people's plans too. 🌍