I have been a software developer at a company for 6 months now. My tech lead is accepting an offer at a different company, and the role has been offered informally to me by him. "Informally" in the following sense: the role of "tech lead" at my company is not an official position. Every employee is a software engineer, but the designation of "tech lead" is informal. However, the position comes with much more responsibility than in my original job description of "software developer."
I have informally accepted the offer, but when approaching my manager about a compensation increase to match the increase in responsibility, he said since all of us engineers are technically "software developers" in the payroll system, he would need to create a new role, and that could take months to years, if it could even happen at all. He mentioned that in a different business context something similar happened, and the person was compensated lump sum for what they would have been paid if the compensation was raised at the time they took on the new position. He also said that wasn't a promise, but an anecdote to show that it has happened. I don't see the logistics of making a new position my problem, though, and I don't care about the title, I just want to be paid fairly for what I am doing.
Some more context: the role of tech lead is so demanding at this job that my current tech lead has split the work with me 50/50, and given me the designation of "Lead Engineer". This is as fake of a title as "Tech Lead" and had no pay compensation increase, even though I was doing half of his job. I told my manager about this, that I am happy to do it, but would need a compensation increase since I am performing over my job description. My manager agreed, but nothing came of it. So, now the situation has morphed from not being paid for doing 50% of the "tech lead" job, to potentially not getting paid for doing 100% of the "tech lead" job.
I am a relatively young engineer, and this is only my second job out of college. I like the company, the people I work with, the tech we use, and even though it isn't perfect I would like to stay at this company. The role of "tech lead" would look good on a resume, but only being at a job for 6 months will not. Not to mention, this is being posted during a pandemic and the job market is extremely tight right now. Is it normal to not be compensated for a promotion like this in practice? Am I being too idealistic? Any advice would be greatly appreciated!