That does seem a big differance… but it could depend on the sensors proximetry to other heat sources like the MCU itself.
I also do not quite understand your routines for reading the sensor values. I have a similar sensor BME280 and can successfully read all aspects, and send a bunch of data to multiple sources, every 4 seconds without any need for delay() nested if() or while() commands. And no disconnection issues. Take a look and see if you can benefit from some of the basic (AKA less code and resources) sensor read functions I use.
@Blynk_Coeur has a point… With Blynk Timer, each named timer can have up to sixteen independent instances before needing to have a separately named one. I can’t be positive, but having two named timers, each for only a single instance, may be more resource heavy than one timer with two instances.