I'm leaving in a week for a trip to Europe and was looking for what are current prices on data roaming carriers. I found one I don't recall. It's GlobaleSim and the rates are very competitive with Airalo and KnowRoaming. Coverage seems pretty comparable also, with their base plan including 64 countries. They charge $18 for 5Gb, good for 21 days of service. These are the covered countries listed for that plan:

Countries covered by this plan

Albania, Armenia, Austria, Australia, Belgium, Bulgaria, Belarus, Canada, DR Congo, Switzerland, Cyprus,
Czech Republic, Germany, Denmark, Estonia, Spain, Finland, France, United Kingdom, Georgia, Ghana, Gibraltar, Greece, Hong Kong,
Croatia, Hungary, Indonesia, Ireland, Israel, Iceland, Italy, Kyrgyz Republic, South Korea, Kazakhstan, Liechtenstein, Lesotho, Lithuania,
Luxembourg, Latvia, Montenegro, North Macedonia, Malta, Mozambique, Netherlands, Norway, New Zealand, Philippines, Poland,
Portugal, Romania, Serbia, Russia, Saudi Arabia, Sweden, Singapore. Slovenia, Slovakia. Thailand, Tajikistan, Turkey, Taiwan,Tanzania
Ukraine, United States, South Africa

I may be giving this a trial run unless there are negative reports about their plan.
Edited to add: They also quote voice minutes may be added to plans starting at $10 for 100 minutes.

Here's a link to their website. I did not find any mention of an App for devices, so I assume you need to log in here to check on an order status and balance if available.
GlobaleSim Site