For Kanji SRS, there is https://www.kanji.koohii.com/ (with 2 i’s), which references Remembering the Kanji by James Heisig, though the website is free. Koohi with 1 i
I heard that jpdb.io can be configured for Kanji learning, in addition to just vocabularies.
There might be other Resources , like https://www.kanjidamage.com/, but I am not sure of the tests or exercises.