Are they? They've contributed a lot of already-legendary Bayraktar drones[1], they've rejected Russia's request to move war ships through Bosporus[2], they're pretty clearly invested in supporting Ukraine despite the unwillingness to impose sanctions on Russia.
[1] https://www.youtube.com/watch?v=TpmfKc96j8Y
[2] https://asia.nikkei.com/Politics/Ukraine-war/Turkey-rejects-...
Turkey is a sui generis NATO ally. The US "claimed it" to get the straits, effectively providing a nuclear arsenal as payment, but it's become very clear that the country's priorities have always been somewhat unique and shifted considerably since the Cyprus conflict - even more so since Erdogan's purges.
Turkey would definitely be a NATO ally in an all-out war (which would be the end of humankind, so whatever), but they will probably never engage Russia directly in a limited fashion while Putin and Erdogan are in power.