3500 DWT is quite large for a frigate, which is larger than the Samudra Joy class.
DWT??!!?? That's not an appropriate measure in this context.
Deadweight tonnage (also known as deadweight; abbreviated to DWT, D.W.T., d.w.t., or dwt) or tons deadweight (TDW) is a measure of how much mass a ship is
carrying or can safely carry; it does not include the weight of the ship. DWT is the sum of the weights of cargo, fuel, fresh water, ballast water, provisions, passengers, and crew etc.
So, deadweight tonnage is a measure of a vessel's weight carrying capacity, and does not include the weight of the ship itself. It should not be confused with
displacement (weight of water displaced by the hull) which includes the ship's own weight, nor with other volume or capacity measures such as gross tonnage or net tonnage (or their more archaic forms gross register tonnage or net register tonnage).
See DISPLACEMENT
https://en.wikipedia.org/wiki/Displacement_(ship)
For a warship, we typically use standard and/or full load displacement
The Dutch frigate HMS
Van Amstel (F-831), a Doorman class M-frigate of the Dutch navy.
Displacement: 2,800 tons standard; 3,320 tons full load
Dimensions: Length 122.3m x Beam 14.4m x Draught 6.1m
That's similar to e.g. Meko 200PN/TN.
This has 16 VL cells mounted up against the portside hangar exterior, initially for Sea Sparrow VL, but now duo-packed with ESSM. Can mount another Goalkeeper forward of the bridge.
Bangabandhu which is our naval fleet leader is sort of small for a frigate but sophisticated and well-armed.
BNS Bangabundhu
Displacement: 2400-2500 tons full load
DImensions: Length: 103.7 m x Beam: 12.5 m x Draught: 3.8 m (12 ft)
It is typically classified a light frigate. Much like the Chinese Type 053H3 or Sigma 10513/10514
However I guess if you count anything with a VLS (even 8 cell VLS) you're looking at exceeding 2000 DWT. If Banglabandhu had to have VLS it would need to be 3000+ DWT for stability reasons.
An 8-cell mk41 selfdefence launcher (i.e. the shortest variant) weighs just 26,800 lbs (12,156 kilograms). A single ESSM missile weighs 620 lb (280 kg), so 32 missiles would weigh 19,840lbs (8,960 kg). So, a Mk41 with 32 ESSM weight just a tad over 21 tons. Why exactly would that necessitate a much larger ship (i.e. 3000 tons, rather than 2000 tons)?
The Dutch ship above uses 16 cells Mk 48 Mod GMLS with 32 ESSM for a total weight of 26,428 lbs = 11,988 kilograms. Single packed with Sea Sparrow VL, that would be 13,278 lbs = 6023 kilograms.
https://en.wikipedia.org/wiki/RIM-162_ESSM
Mind for a semi-active radar homer like Sea Sparrow or ESSM, one needs to have radar target illumination, so you may have to add APAR ( above deck weight < 11 ton) or a pair of Stir 1.8 or 2.4 (the latter each weigh 2.2 ton > total 4.4 ton)
Together with mk41/32ESSM, that makes a worst case scenario of adding 32 tons.
High Performance basically means with stealth, some water-jet technology for short fast sprints (like the USS Independence class) and sensored up to the hilt with a proper command and control network.
It would also mean it has superb three-layer defenses (including VLS) independent of other auxiliary naval assets.
High performance is ust a marketing term. The Chinese ship has not waterjets for sprints (top speed listed as 28kn!) and there a numerous smaller ships that also have stealth features
32 VLS cells are standard. Apparently the Chinese are now offering smaller 4 pack missiles to fit into the single VLS canisters, so you can quadruple the (1st layer defense) firepower just like that. Add to that the C-802 and FL-3000N launchers (2nd layer defenses) and twin CIWS (3rd layer defense) and you've got quite a potent platform.
UAE Baynunah
Depending on ships size, a minimum number of missiles/VLS-cells may apply. However, there are examples of even very small ships with multipacked VLS cells (e.g. 915 ton UAE Baynunah class 2x2 cells > 8 ESSM, in addition to 21 RAM). Danish navy stanflex weapons module holds a six cell vls for 12 ESSM and can go on ships as small as the 450 ton fld Stanflex 300 fast patrol boats. For a larger corvette of small frigate, however, 16 VL missiles would seem a reasonable minimum, in the absense of e.g. a 21-missile RAM launcher.
Stanflex-300 with 6 VL Sea Sparrow, 4 Harpoon, 2 heavy torpedotubes and 76mm
For a given number of fire control channels, adding more missiles just adds to endurance, not firepower/ability to deal with more targets simultaneously. In that sense, a homing missile (IR, RF or active radar) that can lock on before and/or after launchs is more advantageous.
For the chinse HPF, quadpacking would free up other cells for use with different missiles e.g. land attack or anti-submarine.
It is not obvious that 2 AK630 clones and an 8 cell FL3000N make a better inner layer defence than e.g. 2 Type 730 gatlings. IMHO, given where they are located, the small guns aren't even intended primarily as AAA but rather as anti-surface weapon. And each Type 730 can probably engage at least 8 times (I know Goalkeeper can) and can deal with threat coming in from 2 sides simulaneously, versus 1 missile launcher with 8 rounds.