Hardware kits for DSP Lab?
For an undergrad DSP lab, there's absolutely no benefit in complicating what hardware your students need to learn: Let them do DSP on a completely normal PC.
There's plenty of offline processing and real-time capable DSP platforms for PCs. I'd personally recommend getting a bunch of Linux PCs, and having Python3 with scipy/numpy/matplotlib on them for basic algorithms exploration on that.
For advanced topics, like doing live signal processing on audio coming from a microphone or from an internet stream, or doing software defined radio with real SDR hardware, I'd go for GNU Radio, which comes with a lot of useful building blocks, and can be easily extended using Python and C++.¹

¹ Disclaimer: I'm involved with the GNU Radio project, but I do, and I know several educators, use it in DSP/communications engineering labs. Say &quot;hello&quot; on the mailing list.