It depends on your current status in terms of Campaign
If you're starting off and want to drive results quickly, go with the PPC and optimise your onpage keeping in mind the long term benefit of top rankings and free traffic in your sales life cycle.
If you're already doing SEO and have a decent traffic coming in, refer your GSC for the KW that are driving traffic and identify KW impressions with high commercial value or intent to start running PPC ads to find ways to build on your revenue. This way you can quickly multiple your revenue very quickly.
If you're inclined towards PPC don't underplay the value and prospects of free traffic, SEO takes time but have far reaching implications in terms of free traffic, conversions and exposure to diversify and grow in the same niche.
Hope that makes sense.
Amit