I have been with my company as an intermediate software engineer for 2+ years under the same tech lead. In the most recent round of performance reviews, it was heavily implied that I would be promoted to a senior individual contributor role. At the time I was being informally groomed to be tech lead, a managerial position I have never expressed any interest in or, from my perspective, shown any aptitude towards.
During the performance review I expressed concerns that my ascension to tech lead was being treated as a foregone conclusion and that I had reservations about taking on that role. I was explicitly told that this was not the case at all and that I would need to interview for the role when it opened up, ostensibly after I had been promoted to senior.
Instead I was promoted directly to tech lead, which I see as an unequivocal bait and switch. I understand their decision as the former tech lead was also promoted, so as the most senior engineer I'm the most capable person to assume this role. I've been conflicted about this promotion since it was offered last week, but after some reflection I think this is not going to be a viable solution long-term. While I didn't formally accept anything, I was put on the spot and implicitly accepted the promotion when it was offered.
My question is how do I broach this with management? I'm concerned that if I propose taking on the position in an interim capacity, I'll still be stuck in the position given budget restrictions and hiring policies (informed speculation on my part). If I try to refuse the promotion and insist on a senior individual contributor role, my concern is that I'll lose the promotion altogether. Ultimately I suspect they'll insist that I retain the position to try out the new role, as has been the response to my concerns up to this point.
Edit:
I think I left out something important when I edited down for tone: I've been an intermediate for 2+ years because I was passed over for promotion to a more senior position last year. In reality I am a senior engineer in all but title, something management has been telling me for the last year or so with vague assurances that the title would catch up with my role soon. I am a relatively high-performing engineer on my team, responsible for increasingly larger features and a domain expert across some of our most visible products.
Part of my resentment for how the promotion was handled is that I feel I've more than earned my senior individual contributor title and the autonomy that comes with it, and instead I'm being asked to coach junior devs on their career and work on my "soft" skills. Not only does this not interest me professionally, but personally I simply don't think I have the bandwidth to make this work long-term.