Looking for flatshare

Hi. I am an old but fun English teacher, living in Madrid for 10 years. I am looking for a decent person to share a flat with. I prefer to be close the Yellow metro line as this is where most of my work is but I would also have classes online.
I am 62, play padel, design resources, socialise with friends.  I love the countryside. I smoke. I also manage an Airbnb property in the centre.
I could pay upto 500 including all bills
I am looking for September onwards.
Excellent references available