How can I remove the "glowing" feature from objects? It is causing CS:GO to lag

The March 27th update implemented the following changes:

• Refactored low level shaders to fix stuttering on NVIDIA hardware when first rendering previously unseen content.
• Speculative fix for rare crash at the end of matches.

Valve employer vMcJohn on Reddit said that regarding the update they "changed how certain low level shaders work for all users."
A commentator reacted: "while playing, I checked my video settings and it appeared that nothing was different - but my game looked entirely different. Almost like it went on a higher graphic setting. I'm assuming it has to do with the low level shaders you mentioned."
Since 'speculative fixes' have been rolled out in more updates lately, I think the 'refactored low level shaders' might be the culprit here.

More people are complaining, and the problem doesn't just hit people with low specs or without dedicated GPUs.

You could try opting in to beta updates for CS:GO in order to receive bug fixes sooner, or lower other video settings (like the resolution).
Other than that - since you can't turn off post-processing - it seems there is little you can do.

I opened a ticket with Steam Support, and this was their response:

Hello,

Based on your machine's specs you may experience performance and/or launch issues when playing CS:GO that are difficult to provide adequate support for. We have recently seen an increase in reports from users with Intel integrated GPUs with similar issues and we are collecting this feedback and passing it on to the CS:GO devs so they can investigate. Please be advised that developer access to a wide variety of system configurations for testing has been severely impacted by COVID-19. While the CS:GO devs are investigating please keep an eye on the CS:GO blog for updates regarding this issue.

For now we recommend reading our Troubleshooting Game Performance Issues article for general information on improving your machine's performance while playing the game. If the article does not help we are limited in the support we can provide due to the number of unique configurations and settings our users have.

CS:GO remains in constant development. As new features are added and improvements are made to graphical fidelity and sound, the game's practical system requirements will continue to increase. Because of this, troubleshooting issues on machines at or near system requirements is difficult without having physical access to your machine for various testing and troubleshooting.

Because we have provided all the information we have regarding this issue I'm closing this help request. I'm sorry we don't have a fix right now and we appreciate your patience while we look into this.

Jumping through portals, Noki

My GPU is indeed Intel, so I just have to wait for the fix.