I'd never re-use a de-soldered IC...unless it was so unique and not available...but wait there is more.
Trying to remove a QFN144 (edit QFP144) IC for a novice is in the realms of "fantasy" as you will damaged pads. I do LQFP144 ICs and have decades of experience and they challenge me. One damaged pad can be game over.
Its almost impossible to remove such IC without bending some PINs on the IC removed so there is almost no way to re-fit it....from the POV of heat let alone.
Your only chance is to use ChipQuik low melt solder and lots of flux...bridge all IC pins...also include std solder, use 2 irons and a helper to do 2 sides while you do the other 2. Bridge the pads till the IC shifts. PICK it up remove.
Remove LQFP ICs with chipquik:
Thoroughly clean all IC pads with with lots of flux and soder wick....do not over heat do not scrape the pads to twist them or apply mechanical force that damages the pads. Quick, less heat is your goal.
There is a trick method using enamelled wire to lift legs off the PCB but the danger in this is lifting the pad as well.
https://electronics.stackexchange.com/questions/51616/is-this-desoldering-hack-likely-to-workCutting IC legs...will twist the pads and they will degrade.
You may be able to clean the old IC legs with lots of flux, solder and soder wick but more likely you'll bend legs.
Tack in new IC at corner pins. Use a hellva lot of good flux and drag solder the pins. Look up vids on this. Best you actually use a drag solder cup tip. Heat attracts the molten solder so don't fret on multiple pin bridges....more flux and hot iron will draw that away...or some soder wick.
Drag solder techniques Note he's using kimwipes...they are a must to clean pads.
I solder LQFP 144 with magnifier head band and inspect (after cleaning) wit ha video magnifier. You would be surprised at the number of "mistakes".
Remember Flux flux and more flux. Is see users using just a flux pen.....I use far more than that. I prefer rosin but I found Gel is best on these as it doesn't evaporate as quickly wrt rosin. I find I can only get half of one side with rosin before I have to re-apply.
There are Hakko tips that are square 20mm so you can heat all legs at once...but they are not cheap and I'm yet to be convinced they work. I've seen them use in the military in micro-min repair on aircraft PCBs but they also have pre-heaters and the best equipment.
I can solder with my ADSM302 but its not good for these ICs due to DOF and limited FOV. But its excellent for inspection. Dave has reviewed better digital microscopes...but nothing beats a binocular optical microscope.
There is so much to say but......for a novice to R&R successfully is impossible for a novice. I'm sorry...It tests good solderers! I'm definitely not the best and I can manage them, they do test me (I aim for zero pad faults and keep the PADs as cool as possible for future repairs) ...after decades as an Airforce Avionics Tech now doing telescope computers that use similar LQFP144s.
Oh it should have a programming port....probably JTAG.
I'd be looking for a method of trying to read the firmware prior to removal. Not you need a suitable programmer and knowledge of the key chain.....All this cannot be learned in a year or 2!
Look if you do need help PM me and I can advise as much I can but put it this way ...I have 2 vac de-solder dual iron stations, 2 Hakko 936 stations, 3 royel single stations, resistance solder gear, hot air stations......use high quality 63/37 solder enough spare tips solder and flux to last 2 life times...all this is experience and minimum equipment...to me.