I'm also playing Pompey, but I didn't run into FFP or wage limit issues.
Pompey has a good transfer and wage budget, but financially the club doesn't make much money to sustain it - tickets are cheap, sponsorship deals aren't big (for half of the season in L1 there wasn't a kit sponsor deal in my game). I did play way under the original wage and transfer limit to keep the club balance positive. Portsmouth budget is the highest in L2 when the game starts (higher than some L1 clubs), which means that players earn a lot - it also makes it harder to offload them. Sometimes I even agreed to pay part of the player's wage after selling him (I might have been able to negotiate that, but I wanted to offload them ASAP).
I think you could be better at negotiating contracts or are signing too many players.
I usually offer around 60% of what the player would like to get, remove all yearly and promotion wages, as esp. the big 30% on promotion ones can kill you after promotion and try to add optional 1-year contract extension clauses. Usually players revert my changes , but in the next round I slightly increase the wage and app/goal/bench bonuses (still lower than the initial player's demand) and again remove the promotion/yearly clauses and add my own ones. Most of the time the deal is done with around 90% of initial player's demand, without any promotion or yearly wage increase at all. Sometimes when the player insists, I have to go higher with the wage and bonuses, or add a 5-10% promotion increase as last resort, but that happens rarely. It's also hard to reduce the loyalty and agent fees, but that is paid from my transfer budget, so it's easier to keep track and doesn't build up over time.
Still, Roberts' clause also bit me in the *** when I signed Crewe's amazing keeper Ben Garratt with a star contract (29k p/m) after getting to League 1 in the first season. Luckily it was the 1st new player in that window and I kept that in mind later on. Gary didn't get much playing time in League 1 (despite being the captain) and his contract expired in 2018. He was a quality player for League Two though. Hunt retired after 1st season which freed some funds, Baker and Doyle retired in 2018 with Roberts.
So about Pompey - you should avoid signing many stars as your current players should carry you through the 1st season and some of them are very good for League 1 (if you offer them new contracts so they won't get stolen due to low release clauses):
- Burgess and Clarke are my top DCs in Championship 17/18, same as Stevens as left-back
- Whatmough got unfortunately picked by Ipswich due to the low release clause which I overlooked but he had the potential to be even better,
- A. May went on an loan in my first season but he was amazing in League 1 in the 2nd season and is a regular substitute in CH now,
- Close did OK but mostly a rotation player, now backup,
- Chaplin is an ok AMC on squad rotation in L1 and CH,
- Lalkowic has his ups and downs but played fine in L1
- C. Davies was a great substitute DR talent in L1 that got chased by many richer clubs.
At the game start I think I brought only a backup DR and a young striker that turned out later to be **** (Hunt and Main weren't good for my tactics). Hyam loan finished when Clarke got out of injury and I generally didn't have many injuries, just some card suspensions.
In the 1st winter break I did offload some of the players, especially wingers, as in L2 I relied on Baker/Roberts/Lalkovic/Chaplin as attacking midfielders with only a little support from Bennet and Naismith (who both got offloaded later on as I had better players incoming).
Good luck with your game in L1! It's gonna be hard to survive the FFP treatment, but you should get some money to keep you alive after the season from sponsorship, TV and solidarity payments. Maybe try to renegotiate contracts from your backup players and get rid of those 5% yearly increases. If they didn't play much or their squad status got reduced, they might agree for a lower contract. Sign cheaper and better staff using the mutual termination if possible.
might have to bite the bullet and pay some of his wages.