If you have synaptic installed on your system, here is what should work.
Launch synaptic (you will probably be prompted for your password)
Click on Search and search for brave - you should find brave-browser
Click on the brave-browser entry
On the menu select Package and then Force version…
From the dialog presented you can pick from the available versions. 1.0.1 should be listed
Click on Force Version which will close the dialog.
On the menu click Apply, answer Apply on the dialog which comes up and the old package will be downloaded and installed in place of the defective version
Finally select the brave-browser line in the list, Click Package on the menu and select Lock version. That will hold brave at 1.0.1 until you uncheck Lock version.
Those are the steps in synaptic on Linux Mint. The steps should be the same on Kubuntu.
Let us know if that works.
Ken
p.s. If you do not have synaptic you can install it from a command line (terminal)
sudo apt-get update
sudo apt-get install synaptic
I don’t have kubuntu handy but it is probably installed on the menu tree under Administration or just type synaptic in the terminal.