tressygirl's advice is the simplest and easiest.
Otherwise I'm afraid that I suggest that you prepare yourself for the possibility that the seller/manuacturer won't handle this or, if they will, that it won't be for free, or that it'd be cheaper to buy a replacement (they might pay for a replacement but don't necessarily expect it).
(I speak as someone who over decades has bought leading good quality grinder makes and has to replace them every few years. Plus I've bought for or been consulted on buying for small commercial kitchens and thus have researched the items.)
It also depends on how often you use your grinder, too. If the manufacturer suspects or claims you've used it beyond its normal expected wear and tear, or even abused it, then their T&Cs allow them to decline to repair it; unfortunately while I doubt that comes into it, it's them that decide that as they act like judge&jury.
They're often still repairable, but for many lower-cost appliances it is increasingly cheaper and simpler to replace than to pay for diagnosis, parts, postage and waiting time.
The right-to-repair rules mainly require manufacturers to provide spare parts and repair information for certain products. The rules don't require that every fault must be repaired, nor that every fault actually CAN be repaired.
I don't know what grinder type you bought, but it's pretty important to buy the right sort of grinder for the item to be ground. Not telling you to suck eggs but, in case it helps, I have, based on a YTuber's suggestion, tried a top quality coffee bean grinder for spices (and obviously keep to grinding spices only in it, and not put too much in it) as it can sometimes work better than a grinder sold as a spice grinder; but such use is likely to make the manufacturer say you didn't use it for its designed purpose = we're not going to repair/replace it.
If the fault is the burrs (which it could be - you say it's sticking), burrs are usually replaced rather than sharpened at home. Burrs can go slightly out of alignment with normal use especially frequent use. Some specialist services (totally separate from the manufacturer) do offer professional re-sharpening or resurfacing for larger industrial burrs (which you'd pay for; the manufacturer won't pay for that), but most home-grinder advice says sharpening is not practical because burr geometry and alignment matter more than simply "making the edge sharp" again. In the early grinder days some people tried to sharpen/resurface burrs using aluminium foil, but these days it's apparently not advised.
You say it's a cordless grinder. While some can be very close to corded ones for light-to-medium use, something is usually sacrificed: runtime, sustained power, weight, efficiency, robustness or a mix of these (quite apart from having to swap batteries). Corded models still tend to give more continuous, reliable power for long or and/heavy jobs.
