i’m a huge kamen rider fan, i’ve not really watched much sentai sorry
i can’t rec you on that
Den-O ... most popular series of all time, arguably best comedy and characters (i’m biased), it would be a good place to start
Blade/Ryuki ... battle royale, good plot twists? dark
Kuuga/Agito ... dark, mystery (they’re both older compared to the rest, it might be hard to find the episodes)
W ... comedy/drama modern detective
OOO ... comedy, chemistry between two leads, may seem childish but entertaining (for me)
Gaim ... also may seem childish at first but it’s got a pretty good plot imo (a bit fantasy-ish)
Kabuto (my personal favorite), Decade, 555 (brother’s favorites) look the coolest imo
but there’s loads of stuff toexplore, sorry for rambling