Unable to Create Lambda Application

Hi, I'm very new to AWS, so I apologize in advance as I still don't have a decent grasp on concepts such as buckets, ec2, and other services or terms like that.

Whenever I try to create a Lambda application, I get the following error, and for some reason, no matter what I do, cannot get rid of it:

Failed to execute changes on GitHubRepo because: Forbidden (Service: Amazon S3; Status Code: 403; Error Code: 403 Forbidden; Request ID: DJ1YDYFX1CP168KB; S3 Extended Request ID: 9dII7y2P1Pt4/M1KyawdldctRix5yzabYDUeLHLWjaxXVrT3GsJJMzBhAhiymJotStZ20bT8J3s=; Proxy: null)

Failed to execute changes on PermissionsBoundaryPolicy because: Resource creation cancelled

Failed to execute changes on S3Bucket because: Resource creation cancelled

To be honest, I have no idea what this means or how to fix it. After a few weeks of messing around on probably hundreds of forums at this point, I've reached a breaking point where it's about time I admit defeat and ask a direct question. Since a lot of the resources I have visited directed me to mess around with these, here are a few other pieces of information that might be helpful:

• I am logged in as root user
• The roles I have in IAM Management Console are "aws-codestar-service-role", "AWSServiceRoleForSupport", and "AWSServiceRoleForTrustedAdvisor".
• I have tried emptying my CloudFormation stack, but that did nothing but go from one error to another
• I have a github connection set up under "Developer Tools" > "Connections" which I am trying to utilize for this lambda application

Once again, I just wanted to reiterate that this issue is occurring whenever I try to simply create an application, not when I try to upload code.

As a side note, I have faced similar issues with a few other services like Elastic Beanstalk. I have been trying to upload a simple single NodeJS web application (with backend processing) for about four months now, without any success with any service. My goal is to stay within free limits, but honestly, such limits don't really have a meaning if the services don't work in the first place. My current plan is to set up static pages along with lambda to bring database interactions to the website. Any help or guidance about this would also be appreciated, but so far any suggestions have only led to deeper and deeper rabbit holes littered with various errors.