Do what I did, in combination with the HBZ 2018/19 mod just get the latest db in terms of transfers, maybe even change a couple of ratings and potential for players and teams (with CM14) to make it more realistic, since as we know, the official ratings are mostly a joke, especially for less known players and teams, then start your career in 2018 with all of the relegation/promoted teams like they were back in 2018, so that the career doesn't crash, and simulate (I mean still go from day to day like it's normal career, and set up the team for every game, just don't do the full on simulation by the calendar, cause then you'd have certain young players never playing a match and never grow and be unhappy after that first season), so 'play' the first season like you would normally, from day to day, but without actually playing the games, just sim almost all of them.
I myself am doing a Barca career mode right now, and I just got through the first season, I played only the few biggest games (like El Clasico and CL semifinal and final, otherwise simmed every other game). I mean it takes a few hours, but you get there. And turn off transfers in cmsettings completely for the first season (I actually have it turned down all the time, except for the time being that I do my own transfers so they can go through, but in that time I have the frequency of transfers switched from -1 to just 1, so basically no big transfers happen in that one or two weeks that I have transfers turned on, so that I can do my own transfers in that time).
And then as the 2nd season starts, you really start playing the games too, with all the latest teams and possibly even same relegation/promoted teams, if you make all the other Segunda teams that much worse than the 3, who got promoted last season, before the start, so you know they're gonna almost certainly get promoted. Like for example, I play a Barca career mode, and I did that with Granada, Osasuna and Mallorca, although the latter still didn't make it and Cadiz made it into La Liga.
I just finished my transfers in summer of my 2nd season, so I now turned transfers off (only 2 weeks into the transfer window, but my team is set) and only my Barca has some different players, but no other transfers happened in the time I did that, so all the other teams are basically still the same as in real life, as they were in the updated db, which I started the career mode with. And if it gets boring, you can always turn on the transfers fully after a couple of years, although I like them permanently off so the other teams stay the same as they are in real life right now, it's most realistic that way.
And like you said, it's a temporary solution, so I can play FIFA through the holidays. Once HBZ releases a full version of this latest mod in January, I'll probably delete and do a fresh install, so I can start my career normally in 2019 after that. But for now, I'm very happy with what I got, especially since I'm just about to start my first real season, and start actually playing games too, as I'm at the start of my 2nd season in my current career mode, and I'll probably play through at the next 3 seasons throughout the holidays and in January, before HBZ latest mod gets released and I delete everything and do a fresh install.