Erdogan should really ditch buying anymore weapons from Russia. It’s ultimately a dead end and ruins the image of Turkey when they earning really brownie points supplying drones to Ukraine and NATO nations. IMHO, Turkey should make a visible declaration of a break from buying anymore Russian Arms. (Turkey can still get Russian derived products from China)
Spend the money reverse engineering the S-400s and selling the Ukrainians drones in exchange for modern Russian technology captured off the battlefield. Turkey needs to get back into buying western equipment, especially as the west ramps up spending on defense. A lot of R&D contracts and joint ventures with European companies, that can be done, where money and ToT can be procured on more modern equipment then Russia has to offer.