I'm not sure you understand endurance figures. It refers to days you can remain at sea unsupported (with just what you carry), not to mission length (which may well involve at sea replenishment by helicopter and/or support ships)...
Milgem
Range: 3,500 nautical miles (6,480 km) @ 15 knots
Endurance: 21 days with logistic support
10 days autonomous
Project 20380
Displacement: 1,800-2,200 tons
Speed: 27 knots
Range: 3,800 nm at 14 knots
Endurance: 15 days
Minerva
Type: corvette
Displacement: 1285 tonnes
Speed: 25 knots
Range: 3,500 nm at 18 knots
Inhauma
Type: corvette
Displacement: 1,670 tons standard , 1,970 tons full load
Speed: 27 knots
Range: 4,000 nm at 15 knots
Espora
Type: Multi-purpose light frigate
Displacement: 1,560 tons (1,790 tons full load)
Speed: 27 knots (50 km/h)
Range: 4,000 nautical miles (7,410 km) at 18 knots (33 km/h)
Type 053H3
Displacement: 2,250 tons standard, 2,393 tons full load
Propulsion: CODAD, 2 shaft, 2 x 18E390VA diesel @ 14,000 hp (17.6 kW) & 2x MTU diesel @ 8,840 hp (6.5 kW)
Speed: 28 knots
Range: 5,000 miles at 15 to 16 knots (30 km/h)
Type 056
Type: Corvette
Displacement: 1,300 tonnes (Standard Load), 1,440 tons (Full Load)
Propulsion: 2 diesel
Speed: 28 kn
Range: 2000 nmi (3704 km) at 18 knots
These are all fairly normal for ships this size
Now, consider:
Alvand class (ex-SAAM class, a Vosper Thorneycroft design)
Propulsion: 2 Paxman Ventura cruising diesels 3,800 bhp, and 2 Rolls Royce Olympus TM-3A boost gas turbines 46,000 shp (34,000 kW) on 2 shafts
Speed: 17 knots (31 km/h) on diesels, 39 knots (72 km/h) on gas turbines
Range: 5,000 nmi (9,000 km) at 15 knots (28 km/h)
Question: does Iran have that capability to BUILD and MAINTAIN marine GTu's?
Moudge/Jamaran propulsion does not suggest BUILD cpability as the plant is: 2 engine, 2 x 10,000 hp, 4 diesel generators, 4 x 550 kw
Consider Jamaran 2 will be less fast than the original Alvand (since: less than half the max shp of Alvand's CODAG plant). It will also be less fuel efficient than Alvand on diesels alone (more than double the shp of Alvands Paxman diesels). Thus, for given bunkerage (= little design change), it may be expected that (unrefueled) range figures on cruising speed are less than those for original Alvand and more in line with what is common for corvette. Also, I strongly suspect those diesels are of Chinese origin (Shaanxi Diesel) i.e. comparable to the diesels in type 054 (licenced Pielstick engines) and in the Type 056 corvette.
Type 056
Type 056 Jiangdao Class Corvette China Chinese Navy PLAN Guided Missile Light Frigate Bengbu CSSC China State Shipbuilding Corporation datasheet pictures photos video specifications
Type 054A
Type 054A frigate - Wikipedia, the free encyclopedia