Yes the glass lens cover only replacement part is available to purchase, however the cost and delivery may vary depending on where you are located. Below are some links to the parts from a site that claims they use authorised OEM parts.
Disclaimer: I’m not associated with this site nor have I made any purchases so I cannot vouch for the quality. If you want to spend a bit more time doing your own research for it you may find a better source for the parts, but they ''are out there'' :)
https://www.mobiledefenders.com/motorola-repair-parts/g-series/g-power-xt2041/rear-camera-lens-top-for-moto-g-power-xt2041-authorized-oem.html[br]
https://www.mobiledefenders.com/motorola-repair-parts/g-series/g-power-xt2041/rear-camera-lens-bottom-for-moto-g-power-xt2041-authorized-oem.html