We are SO EXCITED YOU CAN MAKE IT!! There are lots of great places to stay around the venue, and since everything is within a ten minute drive, you can't go wrong!
The venue is in Estoril and there are a few hotels across the street. There is not a large town/energy in Estoril so if you are looking for a more bustling energy we would recommend staying in Cascais.
Estoril and Cascais are separate towns, but are very close--you can walk along the sea wall from Estoril to Cascais in about 35 mins and can drive in an Uber within about 10 mins. Think of it more like separate neighbourhoods rather than different towns :)
There are a lot of options on Airbnb and here are a few hotels within various price ranges.
Higher-end
Hotel Albatroz: https://www.thealbatrozcollection.com/albatrozhotel/m/
Pestana Cidadela Cascais: https://www.pestanacollection.com/en/hotel/fortress-cascais
Mid range
Hotel Baia: https://www.hotelbaia.com/en/
Hotel Vila Gale: https://www.vilagale.com/pt/hoteis/costa-de-lisboa/vila-gale-cascais
Villa Vasco de Gama (guest house) https://villavascodagama.com/
Cost-effective
Nice way hostel and surf camp: https://nicewayhostels.com/
Cascais bay hostel: https://cascais-bay-hostel.uoi.pt/
If you would like to stay right by the venue, there are several hotels right across the street:
Palacio Estoril: https://www.palacioestorilhotel.com/?utm_source=GMB&utm_medium=GMB&utm_campaign=GMB&utm_id=GMB
Hotel Inglaterra:
https://www.hotelinglaterra.com.pt/
Evolution Cascais-Estoril (note you will need to cross a busy street to get to this one but it's super close :) )
https://www.sanahotels.com/en/hotel/evolution-cascais-estoril/