My Dr switched me from 0.5mg of Xanax 3 times a day to 5 mg of Valium 3 times a day.

I had to switch from 7mg of ativan to 7mg of valium because of medicines shortage, no real issues thankfully, am now trying to taper off the valium, but am doing it very, very slowly. You should be fine. Wishing you all the very best.

As you are most likely aware high potency/ strongest benzodiazepine is Xanax (Alprazolam) and low potency is Valium (Diazepam).
When it comes to these conversions caculators of benzos, they are not very reliable as many factors are involved in order for one to get an accurate result, as age, dose, gender,weight, etc..

Having said that, everyone reacts differently to medications, but in my opinion you will have very little withdrawal symptoms, which are normal when switching to weaker benzos, speaking from 30 years of experience taking benzos, since I was 25 y/o.
A word of advice in order to make the transition easier is not to get anxious before you start the process, maintain your calm and try to relax, I now it is easier said than done, but I've been there and it's bearable.
Again, not trying to scare, but one must be realistic and have a positive mental attitude.