Very weird to rank for me because while I think that writing is good, and that author still (as of last 103 chapter) provide some great new ideas, since year 3 the overall number of bad and cringe ideas did become too much, and this fic had become a guilty pleasure at best.

Years One and Two were the best one. Alexandra felt like relatable protagonist, Light Side antagonists while definitely antagonists were relatable too and kinda were in gray moral area. When Exchequer was a mysterious organization in shadows it really felt like a worthy antagonists.

A crucial moment when this fic started turning from good to trash for me was end of Year Two. After basilisk defeat Alexandra very quickly turned from relatable underdog protagonist to overpowered Mary Sue: very quickly she gains Zabini's guardianship and protection, receives overpowered Hydra Animagus form, from a girl slightly above book Harry eventually receives status of worthy opponent of Dumbledore and even beyond. Later comes two additional overpowered Mother Figures...And that's not all, but I would not want to spoil too much.

Year Three is complicated. Despite of all of this happening, Exchequer still felts like a threat, Light Side still has some gray aspects, and there are great moments there.

Starting from the end of Year Three, and especially Year Four, it is a complete trash.

British Ministry of Magic was caricature in canon, but now it is turned up 15. Same for Death Eaters except Bellatrix.

Then there are British light wizards and Light Side overall. British... Years One and Two implied multiple Dumbledore allies to be competent. Dumbledore himself... He was very interesting up to Year Three included. Interesting secondary antagonist compare to overpowered Exchequer, hidden in Shadows. Very human and reliable. However, by the Year Four was turned into completely stupid joke. As of now, it feels that except his economic power due to being head of largest Alchemy Cartel (basically being able to create as money wizard gold as he needs, although no immediately), he has nothing going for him.
Same for Neville and other British Light guys, although neither felt as well fleshed out as Dumbledore to begin with, so were transformation into complete jokes by year four did not strike as hard.

Overall Light Side... They were starting to get introduced in Year Three... As complete jokes from the start... With author highlighting how Dark Side is better despite never providing moral reasons why... Except "it is better not hiding that you're evil"... They are literally comically stupid... It is stated almost in each chapter in straight author narrative... They some how receive overpowered powers... Only to Dark Side characters receive even more overpowered Dark Side Powers and stomp then.

Exchequer from around second part of year Three fe facto turned from credible threat to overpowered Alexandria-Mary Sue Protectors. Some readers for around 50 chapters hope they return to antagonist role, but considering they are in this role for a half of very long fic... I do not think this is very likely.

Overall, Years One and Two were 4/5. First part of Year Three is around 2.5 and second half of Year Three is around 1.5. Year Four (almost finished) is 1/5 at best