An interesting discussion on Forgotten Weapons with a US citizen who has been working in Ukraine.
Interestingly when committing about Prigozhin's death they said that he had a special landing operation.
It is claimed that UKR has been successful in its attacks in Crimea, seriously damaging an amphibious warfare ship and a Kilo Class sub.
HI Sutton has also done a video on this and his analysis is that both vessels are lost regardless of whether they can be repaired or not. I think that his analysis is probably the better of those publicly available at the moment.
He states on his Covert Shores blog that:
Aug-Sep 2023: Ukraine lands on and reclaims 'Boyko Towers' gas rigs/platforms in Black Sea.
Sep 13: Ukrainian strike on Sevastopol, reportedly with Storm Shadow / SCALP-EG cruise missiles. Pr.775 Ropucha class landing ship Minsk and Pr.636.3 Improved KILO Class submarine Rostov-on-Don (B-237) seriously damaged in dry dock." on his blog.
"Sep 13-14: Ukrainian USV attacks target Russian tanker Yaz and weapons transport Ursa Major in Black Sea. Russian MoD states that 11 USVs were destroyed, 3 by Pr.22160 Bykov Class patrol ship Vasily Bykov, 3 by naval aviation (likely helicopters) and 5 by Pr.22160 Bykov Class patrol ship Sergey Kotov.
Sep 14: Russian MoD reports a USV attack on Pr.1239 Bora Class missile corvette Samum"
We know that UKR have retaken most, if not all, of their gas drilling rigs west of Crimea (
video) and that UKR attacks on Crimea are increasing its vulnerability (
video). I recent months UKR have been launching a series of missile and drone attacks on Crimea with the purpose not being immediately obvious, but those attacks allowed UKR to locate and map Russian air defences in and around Crimea. Now it is clear why those earlier attacks happened.
They have succeeded in forcing Russian control of the western Black Sea back towards Crimea and I think that they will attempt to eventually move it further east of Crimea. The Russians have been unable to prevent this and at present they don't appear to have the capability to wrest control of the western part of the Black Sea back from UKR. They have effectively lost on sub that is capable of firing the Kalibar missile, reducing the sub force by one. IIRC they had 6 Kilo class subs in the Black Sea. They cannot replace it because Türkiye has closed the Bosphorus Straits to submarines.