The idea that you can assess an engineers ability to code AND collaborate with your team in a 3-5 hour window is just a losing battle. Hackerrank and triplebyte are good for the very large corps to rule people out and slim down the funnel. Not a real reflection of the work, code, or problems you will be solving in the job if hired.
15yrs tech recruiting corporate and agency. I have seen almost every tool out there and I will say very few have stood the test of time. Hiring is really hard and the fact remains there just isnt a one size fits all solution. Find the tools that suit your goals.
Personally I think small companies would be far better served investing in sourcing tools to attract and located the right talent. Have your leadership pitch these people directly hunt talent versus tools to automate volume (95% of which are not the people you are seeking any way).