I just want to mention a few things. Firstly the cost to the Philippines to refurbish these ships without getting any improvement in their capabilities was $128M. The major consideration here should be whether it is cost effective given that to improve their capabilities one would need to put minimum $50million into them for new systems. Not to mention PN doesnt operate Otomat or Aspide (though PA/PAF operate Aspide 2000), adding further logistical costs. That puts these vessels in the same price range exactly as F-22P ($175M) which is a newer, larger, more capable ship. If you really want used ships then I would focus all the attention on getting Australia's Adelaides given PN operates OHP already and with some upgrades could get the Alamghir up to adelaide level capabilities. They will be being retired over the next 2-4 years as Hobarts come online.
Now, some are advocating for Type 054A which would cost something like $285-300M per ship. Others want western vessels (Valor class for example is ~$337M/ship). I argue that developing upon F-22P (using C-28A as a jumping off point) you could develop a very potent (maybe more than Type 054A) frigate for as cheap as Type 054A if not cheaper while keeping much of the work in Pakistan given the fact that PN and KSEW have built F-22P before.
Using C-28A design, move the C-802 boxes into the space previously occupied by the smoke stacks on F-22P, just infront of the hangar, hidden behind doors. That adds to the stealth of the ship. Where they were previously housed, put an 8 cell vls (if not able to do that, then 2 FL-3000N launchers with 24 cells each). Where the current FM-90 launcher sits, get rid of the launcher and the deck it sits on and place 24-32 cell VLS, which will definitely fit in that location. As the VLS missiles, rather than going for Chinese systems like DK-10 or HHQ-16, I would go with CAMM or Umkhonto-R which can be quad packed (that is unless DK-10 can be quad packed). This would give the vessel 96 - 160 medium range SAMs (if you can get only 24 cells in front and cant place a VLS in the current location of the C-802 would give you still 96 Quad Packed SAM in 24 cells. If you get 40 VLS cells (32 in front and 8 more in the current C-802 location) it would give you 160 SAMs. These are all 60km range fire and forget. IF the 8cell VLS isnt possible in the C-802 location (which i think given the space there it would fit, mostly above deck) the FL3000N system would still give you 48 short range (9km (6km for supersonic targets)). SAMs, coupled with 96-128 medium range SAMs from the forward VLS system (24-32 cells)
Keeping the Type 364 and the Thales Smart S Mk2 radars these frigates would probably range in price from $225-280M which is a bargain considering that they have as much firepower against surface ships and far more firepower against aerial threats than the Type 054A.
To put this in perspective one such "F-23P" could bring 125,664 km^2 under radar surveillance and cover 11,300 km^2 with its SAMs. While it wouldnt have long range SAMs, with 96-160 medium range sams in additons to the 2 CIWS and any potential Fl-3000N, it would be able to overcome most saturation attacks and still defend a small-medium sized flotilla (though it is not fleet level defense).