I can help you out and show you an example my team and I have done for both #1 (implementing a sidebar) and #2 (infinite scrolling).
Drop a message at https://speedboostr.com/contact (my dev agency) with your website and email and we'll get you set up with a solution and a quote.
Hope you are doing well,
Ready to help you in the Debut theme, I am ready to enhance the theme as per you wants-
1) I will integrate a menu bar on the right-hand side in place of using Filter
2) Implement a Load more functionality that will look beautiful on your store.
I am a Shopify Expert & want to provide you best & quality support to fulfill your complete requirement as you mentioned, Let's communicate through email or skype to start beginning the work on the store & also for your any query, I would love to answer,
My email - email@example.com
My skype - firstname.lastname@example.org
Waiting for your reply
Hello @Jason_W1 ,
Greetings! I have read both that task and will do needful.
Can you please add me on Skype or email me discuss further. Looking forward to your reply.
Went through your complete requirement and would like to assist you for the same. Please drop me email at - email@example.com so that we can discuss this further.