New shrimp owner, amonia level

Hello! I'm quite new to shrimp and I have some questions/issues.

We got some shrimp from a local fish store, put everything together and the shrimp passed away within 1/2 days except for one.

We didn't think too much of it except maybe stress/not enough hiding spots. So we got some extra stuff for the aquarium and some other shrimp (we thought the solo guy was so alone). When they all arrived they died within matter of hours (including the solo guy). We did the dripping method, so the change to their new home would be smooth.

After this we bought the ammonia meter/ph etc. We now saw that the amonia level of the empty tank is around 5 and we thought that would have been the issue.

Now we have a complete clean new tank with just the amaoznian soil and some lava rocks, the ph is around 1. But when we measured the now new shrimp water (the water they arrived in) that (edit) amonia level is 3-4, extremly high. However they're still alive.

Now we're confused as to how they're still alive, what the proper amonia level is and if we can just transfer them into the lower amonia level water. (The ph is in both waters the same).