Any recommendations on tools/processes for supply chain benchmarking?

I see really great answers here already, so I would only like to add on top of those.
As a leader, I usually ask this question: why do I want to benchmark and where do I want to get with it?
Follow up questions:
1. have I done any benchmarking beforehand (internally and/or externally)? if not, most likely one internal process is best to start with to know where the function/company itself is
2. if I've done external benchmarking before, did we reach the desired outcome? if yes, then as others pointed out, use the one already used and make it a recurring exercise - then you will start seeing results and patterns that need more evaluation to change. if not, then the selection really should be based on what your goals with the benchmarking are - before you pay for it.

L'art pour l'art benchmarking is a vanity exercise and I've seen many organisations fooling themselves with it for long. Please don't do benchmarking just because someone above you was "advised" to do one. Always ask and evaluate if it is value adding in that situation.

In general, I'm a fan of benchmarking, as it brings immense value, but I always make sure that people do it for the right reasons and not just for management reporting or similar.

Benchmarking is valuable. The key is to first decide on what is the scope and purpose of the benchmarking and build a program then define deliverables. Good quality Data is very critical once you are clear on scope and direction.
Gartner Hierarchy of Supply Chain Metrics identifies 17 critical metrics to focus on across the end-to-end supply chain and can guide you to drill down on the focus area to benchmark. Other than Gartner there is the SCOR model as well as an APQC Supply Chain benchmarking actual process as well as a host of others like Coupa. IBM and other Consulting management firms also provide the service.

I would always start by being a good hear to your customers ! Listen to the voice of your customers, enforce understanding of who are your customers, their needs, their sentiments and identify gaps ! This may already be a good start to move towards better world !

Good question and comments here. Thank you for sharing.

I would start the process with, what is the purpose of benchmarking your supply chain?

It helps to define the action's strategy and plan you need to achieve your goal.

If you want to benchmark to see where you are and what needs to be done to move your supply chain to the next level (in terms of operations, profitability, sustainability, resiliency, SC optimization, innovation, etc.) by benchmarking, collecting information, and comparing KPIs with leading companies in the same sector/industry to see the gap and provide a roadmap to move forward.

And, in the process of translating the industry's best practices to practical, achievable goals that actually fit your business needs and ultimately, it must start with the customer, serve and fulfill your customer's needs.

The tools and processes will vary based on what you want to achieve and what paths you take.

Hope that helps.

Based on previous comments, let's assume that benchmarking is to compare internal benchmarks only, not external. For the measurement tools, you can use data engineering ETL tools to automatically extract from your ERP system. Or, you can ask an admin to collect it all and put it into a spreadsheet. For visualizations, Looker Studio is free, otherwise you can use Power BI or Tableau.