The thing is, I saw these two playing in Gibraltar a month ago. It was a match where Gibraltar won by 1-0. I am not saying it as undeserved, but it was not deserved either and the match could had gone either way. San Marino definitely had their chances, yet the finishing skills are so poor at both camps that 0-0 would had been probably the fairest result. The winning looked like an offside to me, but it was passed through VAR in the end.
Moneywise, the player market value shows that the San Marino players are roughly worth 1 million, Gibraltar 1.5. million euros. So to put that value into context it is something a Finnish 2nd-tier club!
The absolute key players at both teams are midfielders. San Marino's Zannoni had half a dozen shots in the 1-0 loss, and from the Gibraltar side the number 10 playmaker Liam Walker was involved in everything, it looks like he is the only player who knows how to shoot or pass the ball. Yet, he is 36 and he tired himself significantly on the 2nd half. If San Marino can keep him out of the ball they are safe.
In case you decide to watch this one out be prepared for silly personal mistakes and stupid decisions, not all the players are professional in any sense, football is just a hobby. For a team like Gibraltar being favourite away is hardly justified.