Okay, now you're backpeddaling. First you were all "If they decided the plot of a story based on a vote, then they clearly don't have any ideas of their own". Which is a direct slam about voting being analogous to lack of creativity. Now you're all "Having a vote is not inherently bad or uncreative". Pick one.
Voting didn't define the writing, only the pairing. Populace opinion on plots is employed by production and writing teams ALL THE TIME. Especially in the US where test audiences are used to see which characters and pairings audiences respond best to before tv scripts are finalized. Voting happens all the time in scripting in the form of marketing research as well. You just don't see it out in the open very often.
But I found it refreshing that they were "Show your love for Wayu and Gen Y and vote for how you want to see his romantic life play out". It had the benefit of keeping people engaged who were desperate for more and unsure of when season 2 would air. It was a great way to keep fans sated who, due to COVID hitting the bl industry so hard, were unsure about the show's future. And it was nice fan service for what is actually a really, really loyal fanbase of Bas'. Myself included.
I'm unimpressed by the argument "The consensus doesn't seem very positive about how well-written season 1 was". You lost me at the word "consensus". Because there's no such thing as a general agreement on the quality of ANY show's writing.
The biggest sign of a show's success is fan ranking/reviews and viewership ranking. And in Asia it did great. Again, season 1 got a 9.4 out of 10 on IQIYI, the Asian streaming service it was contracted to air on. Which is how I watch it. And its premier airing rankings on Chanel 3 were impressive as well. More even than that, Bas had a fun bet going with Dun that Dun would pick him up and take him to dinner if the social media poll rankings for Gen Y season 1 put it in a first place. And if you check on youtube, there is footage of Dun showing up at one of Bas' concert events, picking him up for that dinner.
As for the popularity of Episode 1 of season 2? Well, you may not have liked it, but it hit huge, with an amazingly large viewership. Even just a couple of days after premier airing, it's already ranked 9.7 out of 10 on IQIYI. Hmmm.... 97% approval. I might have to take back what I said about a consensus.
Season 1 had no plot holes, which was nice. I hate plot holes. The Character motivations all made sense in Gen Y's plot. Even when it was a character I really didn't like (points at Sandee), the reason behind why they were pulling their moves was relatable. The comedy was pretty on par for a bl. In fact, it had to rely a lot less on cute Foley than many shows. The dramatic mood was well developed, including when Thanu avoided Wayu while he worked his stuff out. He was torn between what he felt was his possible destiny, his probable duty and his absolute heart. Which was a great bit of tension plot, even though many of us were tossing popcorn at the screen going "Don't ghost him! Use your words, Thanu!
Lastly, let me hit on your final statement. "...having the central relationship of the plot decided by vote halfway through the story is absolutely bad." Says who? Happens all the time in TV, movies, and other media development. Entire sections of movies have been re-filmed after filming was done and post-production was in swing because a rough cut audience screening showed too many audience members didn't like something. Audience polling has even resulted in complete re-shooting and/or recasting of entire episodes before. Audience polling tools are an industry standard. The primary difference in this case wasn't its impact on the plot or whether it was a marketing ploy, but rather its visibility and its fun for the fans who participated.
But just to set your mind at ease, the voting set up for Wayu's relationship status at the end of season 1 wasn't planned suddenly, "halfway through telling the story". It was planned from day one, which was why the actor playing Pharawee was hidden from the audience until the very end.