Thoughts on boutique ER firm opportunity and options afterwards

First time poster here. Recently graduated from a semi-target and have an opportunity to join a very small institutional sell-side equity research firm that is highly specialized and focused on a fairly niche area of the market, rather than covering broader sectors. I've always been most interested in ER, and one thing that attracts me to the role is that it seems like I'd get a lot of hands-on experience early. I'd also be planning to knock out the SIE, Series 7/63/86/87, and probably CFA Level I while working.

My main question is what the longer-term opportunities look like coming from a smaller, fairly specialized research shop with limited name recognition. ER is what I want to do long term, is it realistic to later move to a larger sell-side platform in a major market and potentially cover a different sector, or do most analysts tend to stay within the niche where they started? And how many years on the role should I aim for? The city isn't necessarily somewhere I'd want to stay forever, but the opportunity seems like it could provide a lot of hands-on experience and responsibility early on. Would appreciate any thoughts from people who have started at smaller firms and where that path ultimately led them.