So far I haven't heard something that Samsung is involved in security issues.
Only a few every year with different phones:
https://blog.talosintelligence.com/2018/07/samsung-smartthings-vulns.htmlThe s7 was probably the most recent one where it was actually a flaw with the chip.
But, with all that I would probably trust more the Samsung wallet than an app, those are simply just too damn easy to get exploited, especially since there is now a third party involved with servers that can get hacked and malicious code injected via an app update.