The Vidanta Sea Garden NV can be booked for less than a week using the hotel name Ocean Breeze . They have 1 bedroom suites & hotel rooms ( separate /no lockoffs )
It is separate from big Vidanta by a beach walk but is right in the Neuvo Marina area where you can walk to restaurants .
Villa Varadero is in that area also : In Feb I went & visited it / for the same reason you list - In case we needed or wanted to extend for a few days some year .
Saw the 1 bedroom suites & spoke to a couple from Edmonton who were there 2-3 days . They said in was clean & satisfactory but not fancy .
Sea Garden / Ocean Breeze has a nicer pool , but the beach & sunshine is the same.
There is also Paradise Village - which may allow shorter stays since it is a points system . We have never been there
I am listing these , in case your listed options only allow 7 day bookings .
All 3 are non AI ..
You could also try Bucerias - there are 2 Rui 's as well as smaller hotels .
Not sure what is bookable for less than a week .