Problems for anyone who thinks this is a serious proposal:

1) Shotshells are very bulky compared to rifle ammunition, reducing ammo carried by individual troops and reducing combat endurance. This also means that box-magazine fed shotguns have less ammo with which to conduct suppressive fire by volume vis-a-vis comparatively sized box magazines for rifles, and that's before getting into the issue that most current-day shotgun box magazines have more issues feeding reliably than rifle magazines. Tubular magazines are finicky to load quickly and smoothly for most people and have very limited capacity.

2) Felt recoil on shotguns can be harder to manage than on most modern combat rifles, increasing the time it takes for a wielder to place an accurate follow-up shot downrange. In a combat environment, where most targets will be ephemeral ones darting between cover or peeking out very briefly, this decreases the lethality of individual troops engaging at range.

3) Shotgun effective ranges are too short to deal with drones at any distance beyond the final approach, at which point you better make your shots count given the two points mentioned above, and hope the payload isn't so sensitive and powerful that you hitting it will set it off and injure/kill you regardless; also, non-suicide drones can stand off beyond this distance and make your life miserable in other ways, like guiding in artillery. Likewise, shotguns are also less amenable for engaging ground targets accurately at the farther end of the 100-200m combat ranges infantry firefights tend to occur at (barring specific environments). As a side note, an LPVO is basically useless on a shotgun for this reason.