I’m running a 5e game for 2 that’s still low-level. Sidekicks are available to them, but they choose not to pick any up. The bugbear luchador barbarian (a hugbear) did acquire a mimic pet, but it doesn’t always help in combat. And it’s always hungry.
Neither is a healer, though, so things can get pretty hairy (so to speak). Because I don’t balance encounters, I did have to do something to reduce the likelihood of a tpk. Especially since the random encounters in this campaign are pretty frequent.
My chosen method of handling this was to have both characters begin play with a house-ruled version of the Lucky rule.
Each character has two uses (could have been more or less, depending on starting ability scores) but they don’t recharge daily. Instead, they recharge at the beginning of a session (so, no book-keeping) and one use (per character) is recharged whenever anyone rolls a 1 or 20. I also allow lucky to be used multiple times per roll, if possible, and that includes rolls that recharge luck points.
This encourages frequent use, lends a slightly wahoo feel to the game, and prevents the characters from getting killed by critical hits, which is the main danger early on. It also puts the tools for their survival pretty directly (although not completely) into their hands. Their survival becomes another resource that needs to be managed.
Of course, I also rewarded their very first mini-adventure with a monkey’s paw wearing an inseparable ring of two wishes, but that was just for fun. Those wishes are long gone, now. One was used for survival; the other made friends with the mimic.