What can cause bitcoin node to be slow to sync?

Question 1

I've already fully synced my node, but I've noticed recently that the tip of my chain is occasionally a few blocks behind peers. What could cause my node to be slow to update? My peers have the latest blocks, and I have tried deleting my peers.dat file to rule out the possibility of bad peers. I am using a linux VM to run the node on a laptop, specs as follows:

Processor Model: MediaTek MT Series
Processor Model Number: MT8183
Processor Speed (up to): 1.6 gigahertz
Storage Type: eMMC
Total Storage Capacity: 64 gigabytes
eMMC Capacity: 64 gigabytes
System Memory (RAM): 4 gigabytes

---- Memory Usage -----
Total Memory (kib): 3978600 
Available Memory (kib): 388820
Free Memory (kib): 287200

--- Cpu Usage ----
Usage User (%): 16
Usage System (%): 21
Usage Free (%): 62

Any suggestions to improve sync speed would be much appreciated. I am also running a lightning node on the same computer, and don't want a delayed sync to complicate things wrt maintaining channels because I did notice it crash once, though the reason is unclear.

Question 2

Even along with slow internet speed, slow external drives, or else slow internet, the early blocks in a device's Initial Blockchain Download(IBD) may still appear to sync rapidly. But, once the device has progressed to block ~450, then sync times will slow down notably.