I remember posting this question just after the Reddit exodus so went back to look at my stats from back then. According to the post I’d been on Lemmy for 12 days and had subscribed to:

• 121 Lemmy communities
• 42 Kbin magazines
• 163 total

That was just on this account though, and I have two accounts with fairly different feeds. So let’s say I was probably on a total of around 180-200 then across both accounts, and have been adding them at a slow but steady rate

That gives us a scientifically sound estimate of my current total subscriptions: a lot.