I started off with Splattershot when the game released as I could not build proper consistency with VRoller (previously part of my S2 weapon pool), and Zap was considered mediocre when Cooler was weak. NTri was briefly part of my pool as I had played it in S2, but it has since fallen out of my favor.
When Zones was my weakest mode, I picked up Heavy Splatling in last April, despite having no backline experience - only a sprinkle of Mini experience as far as splatlings go, and a long-held belief that if I were to play backlines someday, it would be splatlings. In almost no time at all, Heavy became a staple of my weapon pool. I dappled in Ballpoint towards the start of the game and with a new interest in playing backlines I began tinkering with it, trying to build up mechanical skill, motivated by how it ushered in the end of Crab Meta at the time. It was around this time that I finally got 5-stars on the Splattershot, and now I'm juggling time with the Hero Shot to get the fabled 10-stars, but progress has been slow considering my enjoyment with Heavy...
Over the summer, as I played more and more I found myself racking up significant time in both the Heavy and Ballpoint, with Heavy 5-stars obtained towards the end of Sizzle Season, and Ballpoint 5-stars obtained a few weeks ago. It has progressed to the point where Heavy is probably my most comfortable weapon given its great flexibility and ease-of-use, and Ballpoint is just really satisfying to pop off on while hearing the click-click-click of shifting the firing modes, plus its additional range and poking tool over Heavy, which helps with some matchups. I've also been using the Nautilus a fair bit recently and enjoy its additional aggression but still trying to get over playing passively with it, plus mechanical inconsistencies like was my major issue with Ballpoint initially. I just find the splatling class to have the most satisfying kill potential of all the line-of-sight weapons - charger pierces are cool, but I love firing a barrage of bullets on a completely helpless enemy who is unable to approach me directly. They're also pretty good for getting assists!