!rant
I have my 121 in a few days with my new manager and am trying to get a raise either through moving from junior to mid level dev or being given a significant raise , am being paid a tad below the London market rate's lower range for my skill level.

Any advice on how to approach the topic?

Some bits of my background:

I got almost 4 years of exp :
almost 2 working there...
6 months short term contract as a ruby sql dev another company...
1.5 years worked for an abusive joke of a company who took advantage of my naivety since i was fresh out of uni ( did stuff like pressured me to add more features to a pojo system i made for them) barely learned anything there since i was the only IT person there developing solo, the project lasted 1.5 years and was a total mess to finish, so am not too sure of factoring it into my years of exp.

My Qualifications are:
bsc in information systems
Msc in enterprise sw engineering

My "new" Manager is seeking to retire real soon.

The company isn't doing too well but we just landed 2 big customers who are buying the product my team is working on

I Am one of two last devs on my team and we are barely holding on with the load, can't afford the time to train a newbie to join us

my department is soon to be sold (soon according to what mgr says). They have been saying so for 10 months now.

Last year , since the acquisition Is taking so long and funds were running out We were hit by a wave of redundancies which slashed our workforce in august/ july, told we could last till march this year on our funds . Even senior staff were on a reduced work week...but since we Got new customers then money should be coming in again , this should mean thats no longer the case. Even the senior staff have returned to 5 day work weeks.

Am being given only JavaScript work to do despite being hired as a junior java dev, my more senior colleagues dont wanna even touch js with a long stick

Spoke to 3 recruiters , said they got open roles in the junior- mid level range that pay the proper market range if am interested to put my cv through.
Thats like 25% more than I currently make.

Am a bit scared to jump into a mid level position in another company because i lack a bit confidence in my core java skills.
although a senior dev who used to be on my team thinks i can do it.
i recon i can take on the responsibilities of a mid level dev in me existing company since am pretty familiar with the products

I dont get to work with senior devs and learn from them since we are so stretched thin, hence am not really getting the chance to grow my skills

I know i have gaps in my knowledge and skills having not been able work in java for a while hasn't allowed me to fix that too well. I badly need to learn stuff like proper unit testing, not the adhoc rubbish we do at the moment, frameworks like spring etc

Since I have been pretty much pushed into being the js guy for the large chunks of the project over the last year , its kinda funny am the only guy who has the barest idea how some of the client facing stuff works

The new manager does seem to be a nice guy but he is like a politician, a master bullshitter who kept reassuring all is well and the company is fineeee (just ignore the redundancies as the fly past you)

The deal for thr aquisition seem to have sped up according to rumors
And we heard is a massive company buying us, hence things might pick up again and be better than ever

Any ideas how to approach the 121 with him?

Any advice career wise?
Should i push for a raise ?
promotion to mid?
Leave to find a junior to mid level position?
Tought it out and wait for the take over or company crash while trying to fill the gaps in my knowledge ?

Sorry for the length of this post