I personally use GrowthLead.io. The program is cloud based and if you use in tandem with sales navigator will cost you $150 per month. I agree though that cloud based is the way to go. It will always run and it is much harder to detect.
Growth Lead also has a great feature I have not been able to find elsewhere - you can actually tag prospects in sales navigator and let the automation run through it, making your outreach way more targeted. The problem with most automation is that it runs off a generic search URL, and even if you get granular with filters you will always connect with people that don't make sense. An example of this is if you wanted to connect with an owner of a SaaS, every single owner of a SaaS marketing or SaaS consulting company will also show up.
There are also integrations so if you connect, the tool with scrape the email if available and you could zap directly in to an email follow up sequence.
Lastly, if you wanted to run an agency you could do it with this software. Literally one login and you can manage all the accounts you are working on.