There are two methods of traction on the Play store: you can either release a lot of low-quality free apps lousy with ads and hope that the sheer number of apps makes up for the fact no one will spend more than a few minutes with your game, or you can try to cultivate a user base around a single game. I won't lie: from your question it sounds like you are doing the first. The idea of a sequel is brand recognition: nothing more. It's why franchises exist. People who liked and played the original are excited to play it, and hopefully their enthusiasm plus a new title will encourage new buyers.
A sequel by itself doesn't do that. A sequel in a unknown, relatively unknown or even just lightly known 'series' is as disposable as the first title and in that case you'd be better skipping the sequel altogether. I mean, what demand is your sequel trying to meet? Unless you have some sort of fan base to fall on, some sort of reasonable DAU or download count, there's no one even looking for a sequel. And even then, a lot of players who enjoy your game will probably just want you to update the original with new content since they already HAVE that App and invested time and energy into it. Which again you'd be smart to just make a new game since the people who enjoyed your first game are more likely to be interested in what else you do, not just a sequel specifically.
Short answer: unless you have some kind of annualized franchise and a player base to back it up, sequels are not something you should be planning ahead for. You have no idea how successful, if at all, your first game is going to be and diverting resources away from development and QA to get a head start on a sequel can only hurt your initial game. However, it's your choice. When you start your next project is entirely up to you, just know time spent planning sequels before you even have an audience is time that would have been better spent on the first game.