This can work out if you give it a try:
Clear all the data saved from the browser like cache, third party data, saved forms/passwords cookies & rest. Also make sure the shields are enabled [Advertisement blocking modules & anti-fingerprinting modules] Try browsing the page again.
If this doesn’t work, I’m afraid you’d have to run a malware scan on your local device
Emsisoft Emergency Kit is a Free Second Opinion Threat scanner. Here’s the download link:
Execute the downloaded file, enable PUP detection & run a FULL SCAN using “Custom Scan” option
Also make sure to click only once while opening brave. Usually on a low end device with 4GB or Less RAM, brave takes a couple of seconds to boot-up
Hope this helps