Teen Rebuilding Seo To Save Family Business

Hello guys, thanks in advance for reading :)

My family has got a small business on which we all rely on. This last year sales have been slowing down, partialy because we had an agency change our website and they did an awful job, so we lost about 30/40% of our traffic and sales.

We can not afford another agency or freelancer to work for us so I have been getting into SEO for the last 10 days so I can rebuild with WP or Lovable and SEO our asses out of the situation pretty much.

We live in Spain, Europe. The province we live in has got 100k inhabitants. 60k in the capital (which is 10 miles away from our village). We have got a house which we use as AirBNB (not the same as we are kinda independent but yeah) and our website has got a little authority (about 13). Only competition is Booking and couple other more sites for Spain, I have made some reaserch and we can rank for some good keywords if done properly.

But I still have got some doubts which I hope yall can solve: My Ideal Customer Profile are families, groups of friends, couples out for romantic weekends and aviators (EU's greatest aerodrome is 2 miles away).
The house has got a really cozy and private backyard with a chill out, barbacue, heated swimming pool, trees and a lot of green.
The house itself used to be a stable but was restored by my mother and father, it is really cool on the inside and the decoration is on point. There are plenty activities on the area and plenty places to visit which are incredible as well.

So my question is, considering all of this (and considering I will be migrating the web and trying not to loose the autority with the relinks and 301's), how should I build the web?
Should I make a /home, /the house, /surroundings and activities, /blog, /contact?
Should I make aditional pages within /the house to rank for keywords such as heated swimming pool, backyard, barbacue as H1's?
Should I make a section in the navbar for the different types of groups such as friends, family, couples, aviators? (These are keywords with good volume and not that much competition so ranking for them with individual pages might be good)

I am really lost and dont know how to proceed, and I CANT AFFORD to FAIL HERE.