Though I'm all for bringing in more English players — mostly because there are SO MANY good young ones in the Prem/Champ — I think you're focused on the wrong thing. Selling three super promising players in their early 20's (Ndombele, Dele, and Foyth) while their stocks are depressed is a terrible idea. And all the others you mentioned, aren't likely going to bring back much money.
Pochettino spoke a lot about a "painful rebuild" and "painful" means selling some guys who you don't want to sell. I fudging love Sonny, but he just turned 28 and has been here for 5+ years. Losing him will hurt our squad but driving him into the ground for two more years and then selling him much less isn't good squad management. As hard as it is, same goes for Kane. If you can realistically get huge money for him, does it not make sense to let him move on as a club legend and reinvest that money in the best young talent around. Many of whom will be British.
Lo Celso, Ndombele, Sessegnon, Dele, Bergwijn, Foyth, Dier at CB, Sanchez, and Winks are some really nice longterm building blocks in the squad, and we need to be smart about WHICH veterans we keep around to support them and which we sell at the peak of their value. Big teams know when to buy AND when to sell, and we've been terrible sellers in recent years.